It is possible Japan has a higher cost of improving electricity generation and distribution versus the inefficiencies of hydrogen and distribution. Personally I see EVs as mobile, power buffers which I think Japan is better equipped to handle than the USA. But without doing a study of the Japanese grid, I'm not in a position to cast stones. That remains a problem today in the USA. Electricity to battery and wheel is ~2-3 times cheaper per mile than any hydrogen source to fuel cell powered wheel. Bob Wilson
Uh, those experiments haven't worked well, for example Hoover (mining engineer.) Not to be confused with Dyson. Bob Wilson
And when the tax credit goes away the lower priced (see MR model 3 in response to credit going to $3750) SR will fill in the gap. I understand where you are trying to go with this, but you are not making any kind of point whatsoever. I wouldn't waste thousands of dollars on a vehicle that plugs in for 20 miles, especially in MN where you can't use all-electric after the temps drop below a certain range. For most people that money is better spent on a car with FAR better features, safer and doesn't require you to burn gas that sits in the tank for months should your commute be plug-in only. The hybrid is going to be phased out, and it's sad that Toyota is going to be drug kicking and screaming into the future.
Then buy a Prime instead. I live in Minnesota. Watch my videos. Toyota already produces electric-motors, controllers & chargers, battery-packs, and a rather impressive heat-pump. They are setting the stage for large-scale customer acceptance of plug-in vehicles, as well as refining their production & software along the way. 
I thought he invented the sphere..... Primes this year are...what? Up twenty five percent over last year? Given the soft market for Priuses, relatively low prices for fuel (other than Prop 6 territory!) and the Prime's limited EV range, I'm thinking that the folks in Aichi ought to be back slapping and ordering champagne. In some circles, 25 percent year over year is fairly big - but.......you gotta do it again next year!
Except Toyota has to put cash on the hood of a low margin car in states that don't have the generous state incentives. For those that qualify for all the incentives, and can live with the drawbacks, the Prime is cheaper than a Prius in some states. Then lets not forget the Prime likely won't hit the 30k annual Toyota predicted. Sales are strong in Japan, which is what Toyota really cares about.
The low price of fuel provides little headwind for plugin vehicles. 25% YOY is a good solid result. However, when you consider the plugin market grew 100% YOY it is a bit lackluster.
What prediction? There was a target set prior to rollout, but that was contingent upon worldwide distribution. This is the same old spin we saw when gen-1 was in play. People misrepresented both milestones & audience.
Possibly if interest: Volvo, Tesla and Cadillac worst in Consumer Reports latest reliability report | Fox News Most significant to me: "If you're slow to the market, you're slow with technology, that's the way you do get reliability and that's how Toyota is so consistent,"
Don't forget California disqualfied older plug-ins from free HOV, so that is one reason many Californians need to get new plug-ins. Between that and the reduced Federal credit for Tesla's, there are some reasons for higher sales this year. We will not know final Ca. 2018 sales until Feb_2019, but so far this year Ca. is running 55% of plug-in market versus maybe 46-47% in prior years. In one article posted here a while ago, Clean Technica I believe quoted that 75% of plug-ins on the road are in Ca, but since sales are ~50% in Ca, I don't know if that means a lot of older plug-ins are off the road now or what?
It was 60k Globally, with 30k for North America. So they might hit it counting sales in Canada. Doesn't change the fact that they are discounting a low margin car to get them off dealer lots. As a counter to @ETC(SS) claim, I mention it because Toyota may not be happy with their costs to get that growth.
25% looks fabulous, until you look at the numbers, and how they got there. and then there's always 'what might have been'
That's a good point if the Prime is a loss-leader. Unfortunately, only one company is leaking their profit margins - and they have a somewhat troubling relationship with being truthful.