I agree with you in general, except for this part. I think 2020 is a bit early. Elon himself has projected 500k Teslas produced in 2020. US car sales in August were at an annualized rate of 18.2M and rising (
source). Even if several other EV/PHEV models sold at levels of 500k/yr in 2020, it would still be a stretch to see plug-ins account for a quarter of all new sales.
So here's my radical thinking. I'm fine with scepticism on the year. Focused on US only, if that's an acceptable preface.
1. EPA and akin produces tougher regulations based on growing environmental concerns (September 2015. check. Thanks, VW!)
2. Every major manufacturer is selling at least one full BEV with 200+ mile EPA range. 2017-2018, except Toyota and their Hydrogen thing...
3. OPEC bleeds the competitiveness out of the Williston, ND shale oil fields by keeping prices too low for too long, then dials back hard in 2018-2019
4. Oil jumps to $200 a barrel. 2019-2020
5. EV pack price for batteries (not cell price) are at or below $100 a kWh, anywhere you shop by 2020
6. The Millennial generation enters actual income generation, but prefers autonomous car sharing (more time to snapchat) by 2020
7. Most Baby Boomers are retired by 2020 and maintain what they own because, well, Oldsmobile is out of business anyway. <rim shot>
8. The world runs out of crude oil. 2055-2060. Don't take my word for it: BP did the research!
Play with the dates, but that's my sequence of events.
I did say "stuck with an expensive choice" and I mean that specifically. What EV owner with 100,000 miles of experience owning an EV would ever buy an ICE again, given a no-compromise, more affordable option? I think EV ownership is a one-way door. Do you work on a farm and need to tow a trailer with 10,000 pounds of hay, or a horse trailer with four horses in it? Yeah, you're probably still buying gas/diesel pickup trucks for at least another 7-10 years. However, it is an expensive choice and you know it because nobody is making it affordable for you. Are you fixated on the Alfa Romeo brand? It's a thing of passion: you can't put a price on love. For everyone else, though, economics, convenience, I still maintain 2020 is a tipping point on the choice of an electric car. It will be an even choice by 2020 for total cost of ownership, pushing into more affordable to own an EV every time a manufacturer releases a new model.
The #1 to-do here is charging locations, especially for high density housing. There are certain income brackets who I think are really going to want the cheaper option of an EV but not be able to solve the charging logistics.
Oh, final dig: does anyone think that hydrogen stations are going to be 1/10th the density of EVSEs or petrol stations, at any point in the future?