> I ask in all seriousness since, for example, retrofitting regular semis to electric requires millions and millions just to get started

That's because semis - just like cars - are road legal and everything has to be done by the books. The hard part isn't swapping out the engine and mounting a battery pack, car modders have done that for decades for funsies, the hard part is getting it certified for roadworthiness.

On construction sites, particularly ones fully on private property, no one gives a fuck about the equipment, at least not until someone gets hurt, maimed or killed.