Reagan took the solar panels off the White House for a reason, so his buddy James Watt could kill off any alternatives to fossil energy. That regime lasted until the 90s and by then any memory of the oil crises in the 70s was long gone.
The panels installed on the White House were not photovoltaic solar panels - they were solar water heater panels. (After they damaged the roof, they weren't replaced after the repairs were done.) It wouldn't have been possible to run the economy on solar water heater panels.
I’m not the biggest fan of arguing about alternate history, but this thread originally spun out after an ancestor poster claimed we would have a rosy present if only we had invested more in nuclear energy. I claim I find way more wishful then claiming the same about renewables.
On the other we have a technology that still doesn't exist in the 2020s and would also need to be build out.
Cockroach archeologists will be puzzled why we chose to go extinct.
You keep saying this, but I'm not sure where it's coming from. Reading upthread, my interpretation is that we are specifically talking about the technology that exists today, in 2022.
I think it's entirely reasonable that, if investments into renewables were made in the 70s and 80s at a level comparable to investments in fossil fuels or nuclear, we would have seen, in the 90s, renewables technology comparable to what we have today. No, it wouldn't be the same technology, but I could see efficiency numbers being similar, though perhaps at a bit higher cost.