Thanks for sharing your insights. The reason I think it will be faster than the transition to ICE is simple: cost, and ease. When ICEs were introduced, they cost MUCH more per mile to buy and use than horses, and continued to for many many years. Horses don’t need spares beyond shoes and tack, and their fuel is usually relatively free. People will hold on to their cars out of habit, but I can tell you from personal experience when you get used to the idea of taking a shared car you quickly realize all that stuff you are carrying around because it’s effortless to do so isn’t really needed. The miles driven in urban and suburban areas, for most people on most trips, are pretty straightforward — home to work, work to shops, shops to home.
Regarding storage — the cars aren’t the problem, they’re the solution. Here in California we already make too much power at peak sun times. Cars with batteries will become arbitrage opportunities, buying cheap when it’s available and then selling back when it’s more valuable.