I've long though ice sales should be limited to 2% of all sales. That gives an easy out for any niches where ICE actually is compellingly better, but still forces everything else to switch. (travel to the north pole for example)
Not likely. Well in 2031 the rich might buy them, but by 2040 it will be obvious to the rich that regular gas stations are going out of business. 2% of all cars is not enough to support a nationwide gas station network, so the rich will buy expensive electric cars to ensure they can drive. By 2040 the only people buying gas/diesel cars are doing something that cannot be done with an electric car - trips to the north pole is the only example i can think of - but the beauty of saying 2% can be ICE means if there is something I can't think of it can still be covered in that 2%. 2% is also small enough to ensure gas/diesel will become hard to find and so people who resist will still switch to something else.
Gas will still be available, but it will be something collectors buy, and those cars are not driven daily. We know how to make renewable gas and diesel. It costs 4-5x as much $ vs a simple oil well, but it is also a better fuel (it is synthetic molecules so engineers can choose the properties) so those left using petrol will probably prefer it.