The same thing won't happen with solar, it needs active use in novel areas. Cars are out in the sun, why not collect it? Panels aren't exactly a super rare resource, we could and should make piles of these and stick them to everything, it's literally free electricity and basically 0 maintenance.
Are they? Cars spend a fair amount of time under things that would block sunlight; there are garages in all sorts of buildings from your bare-bones detached house garage to multistory affairs, and even if they're outside they're often parked under trees, or in streets and lots shaded by buildings. So it makes already intermittent solar even more situational.
In fact, in hot climates, people take care to park their cars in shade, because the last thing people want is for their car to be baking in the sun.
The ICE brought about big gains for its use case even as a prototype; ICE cars don't produce poop and they wear out a lot less quickly than a horse. In comparison, flying cars or amphibious cars never really made it off the ground in a big way, because the "innovation" there resulted in a hybrid machine that did two jobs poorly and impractically, rather than having two specialized machines.
If it is really easy to point out inherent problems, like, say, the fact that most of the surface area on a car is not generally oriented at an angle to the sun conducive for generating electricity, and those aren't problems that would be solved by "innovation", why try to squeeze water from a stone?