To add a plug to a Toyota hybrid, it's only a matter of adding a one-way clutch.  That allows the second motor (usually used as a generator) to contribute the extra power from the larger battery-pack to the wheels.  It's a bump to performance with minimal cost... exactly what good design should deliver... which confirms Toyota had planned ahead... making claims of resistance an act of denial.

It is interesting how those antagonists will spin that careful planning & patience as a narrative about "dragging".  For that to be accepted, readers must dismiss facts to the contrary.

Equinox Diesel.  Rather than spreading Volt technology to other vehicles, GM decided to focus on diesel instead.  That's something even those wrong focus enthusiasts have a difficult time dealing with.  That's evidence of just plain not caring.  What a waste.  The spin was quite amusing.  They try to portray the situation as just one of disinterest.  We tried.  Customers weren't interested.  End of story.  It isn't though.  Reading though one article on the situation sighted the hassle of "needing to refill the Diesel Exhaust Fluid".  That's a major downplay, not journalism.  Have they provided detail, you'd end up wanting even more.  I remember estimates of needing roughly 7 gallons for every 15,000 miles.  Think about where that fluid for cleaning emissions (it's urea squirted into the exhaust).  You need a tank, a means of filling it, and the pump/squirt equipment for it to operate.  That space, weight, and cost never mentioned by any diesel supporters.  Curious, eh?  By the way, if the system runs out, it is supposed to halt vehicle operation... like when you run out of gas.  So, the effort on GM's part to roll that technology out for diesel models of Equinox & Cruze was a means of evading the obvious.  Volt should have had a successor.  Imagine what things would have been like if Equinox or Cruze would have been given that technology from Volt; instead, all that "range anxiety" work was just abandoned.  Such wasted opportunity.  Ugh.

Most Don't Bother.  A few of us on the thread discussing sales in Europe provided some numbers to consider.  I was one of them:  Avoiding detail is a common tactic from those unwilling to face the reality is actual sales.  Pointing out how to best use the limited quantity of battery-cells currently available is an excellent means of stressing how a small number of EV sales achieves far less emission reduction than a massive number of HV sales.  Put it this way.  1,152,108 Toyota/Lexus brand vehicles were purchased in the United States in the first half of 2019.  Of that total, there were 110,267 hybrids.  That's just under 10%, which is pretty much a solid 10% now due to the rapidly rising demand for RAV4 hybrid and the introduction of Corolla hybrid.  Take that quantity and say each one uses an average of 1 kWh worth of battery-cells. 60 kWh capacity for EV would reduce supply ratio to just 0.16% of overall inventory.  Why would a dealer bother when such a tiny quantity would be available?  It makes no sense... which is why most don't bother.

This is why having more battery-cells available isn't a priority.  Focus currently needs to be on the market itself.  Then when demand grows, that helps with the major decisions of where to actually setup that production and how much each location should deliver.  Rushing that part can be a costly mistake.  Think about how suppliers are already struggling with change.

True Change.  The enthusiast trap is a simple one.  You become fascinated with a new product, then lose sight of the bigger goal.  That's so common of a problem, many fight to a bitter end without ever really figuring out why their dream fell apart.  Oh well.  All you can do to provide reminders of purpose.  Today, it was with regard to how successful the progress forward has been for Europe:  The point is to replace ICE choices with HV, PHEV, EV choices.  That's exactly what Toyota is very successfully doing.  They are transforming the showroom floor, appealing directly to loyal shoppers.  This isn't about the subsidized conquest nonsense we saw with Volt from GM.  This is about demonstrating to their customers (dealers who purchase inventory to sell) that embracing hybrids will feed a growing demand for more and more electrification.  Automakers are a for-profit business.  No matter how great a technology may appeal to enthusiasts, is makes no difference to the bottom-line.  Far too many don't take challenges of having to achieve high-volume profitable sales from ordinary consumers seriously.  Seeing Toyota/Lexus reach that tipping point in Europe, where more than 50% of the sales are now hybrid is a landmark achievement.  That's what represents true change.

Already Delivered.  Things get really interesting why rhetoric turns to outright lies.  It's so easy to disprove claims, you have to wonder if anyone falls for that nonsense.  Based on my observations, that type of activity tends to soar interest.  That's why moderators sometimes step in to deter the behavior.  Bringing down the integrity of their forum will indeed make people lose interest.  Anywho, you have to watch for them, then callout their post when found... which is exactly what I did upon seeing a post providing a suggestion of what should be done to make the idea appear untried:  88% is my EV drive ratio with 2,350 miles on the current tank.  Your "Most of the time Drive in electric mode, and use the ICE engine only on long routes." has already been delivered.  Toyota's focus now is affordability. They are spreading their newest hybrid system, which is easily adaptable to support a plug, across their fleet.  That will bring about not only economy-of-scale reduction of cost, that also provides a strong endorsement for the technology itself.  Also, keep in mind that size of the battery-pack itself matters less and less as more businesses offer chargers for their patrons.

Dead.  You can't help but to be amused by posts like this: "Hybrids are dead, as they should be."  That's a desperate attempt to spin a narrative of assurance.  It doesn't work, since such a reality is fictitious.  Nonetheless, you see them on a regular basis.  This time, I punched back with cold-hard numbers:  110,267 purchases of Toyota/Lexus hybrids in the United States alone the first half of 2019 contradict that claim.  275,300 purchases of Toyota/Lexus hybrids in the first half of 2019 for Europe.

Neglect.  It makes you wonder how the big blogging website for plug-in vehicles continues to push a perspective like this: "...but with just 1,100 Prime sold in H1, it's neglecting plug-ins."  Seeing that on the subtitle of an article posted about Toyota European sales for the first half of 2019 was troublesome.  Was that included to stir participation, knowing it would result in some rather passionate posts?  I jumped in immediately, with this as the first comment:  It made no sense stocking up on model about to become outdated.  Those paying attention know that 2019 inventory was extremely low due to 2020 rollout on the way, which is a mid-cycle upgrade.  That newer model will introduce center seating in the back (the real thing, not a mock spot like Volt had) along with a few refinements to interior features.  The entertainment system gets Apple CarPlay and Amazon Alexa.  There is no way to spin that as neglect.

Think about what the visibility of more chargers does for those considering a plug-in purchase.

They Already Have.  This rhetoric was especially interesting to respond to: "I still don't understand why PHEV manufacturers didn't follow the Volt model.  That is a PHEV (strictly speaking it's a range-extended short-range BEV like the BMW i3 REX) that could be used purely in all-electric most of the time."  That second sentence was a confirm the person had no idea how Volt actually worked, that for possibly many years he has been spreading misleading information.  Without additional context, that's difficult to assess.  With a preceding sentence describing PHEV choices, you get a better idea of the mindset: "But most models on sale now or being introduced have pitiful all-electric range and impotent performance."  Those colorful metaphors are a dead giveaway of a problem.  They are insulting and extraordinarily vague.  To belittle & mislead is exactly the type of response antagonists post.  Hopefully, my reply to that had some type of positive impact:  They have already.  The common narrative would have you to believe otherwise though.  It's a successful effort to undermine.  Prius Prime works exactly as you describe. My EV drive ratio is 87% with 2,261 miles on the current tank.  It will only get better over time too.  As more chargers become available at retail & grocery locations, the opportunity to recharge while out & about will rise.  That will push the EV miles even higher.  Don't believe the rhetoric stating "short" range and "anemic" power.  Those claiming that have an agenda to push a purist approach.  That's really sad, knowing we have such a diverse market.