Humanity also could build a carriages being polled by ants and us that instead cars. Jus it doesn't mean it's a good idea, or should be done . .
Unlike the absurdity you posted, building-integrated photovoltaics is a legitimate technology with obvious advantages. If power generation could be easily and cheaply combined with conventional construction technologies, the reduced costs and ecological impacts would be immense. Your treating this technology like some kind of absurd magic reveals nothing but your unabated ignorance of said technology.
. . . , especially from everyone's public money.
How the hell do you expect to be able to modify public roads without public money? The very nature of such a project requires it to be public. Maybe you are against public roads?
This money could be better spent researching THE MATERIALS
Oh, just like how the conventional solar industry has started booming because everyone focused 100% on material research alone instead of economies of scale? Except that is exactly what did NOT happen!? It was the economies of scale that created the virtuous cycle of innovation and up scaling we are seeing today. NOT the Ivory Tower. . .
Solar power is incredibly cheap, decentralized, and easy to access. Treating it like another Ivory Tower technology like fusion is exactly the WRONG approach. It is SOOOO much cheaper than other energy projects that trying all sorts of crazy, bold things with it is exactly what is and should be happening.
The first 90% of a project takes 90% of the time, the last 10% takes the other 90% of the time.