People seem to be missing something important about this suggestion:
In a market system where solar pv is an option, per-residence efficiency and effectiveness matters a lot and the objections raised here makes sense. But a mandate that all new builds come with solar pv changes that logic fundamentally.
You are now in the domain of grid-scale distributed energy production, grid resilience, and production scaling that will force panel prices much, much further down. This is an infrastructure change and should be considered in those terms.
I would personally have started with residential energy storage for the same reason, but honestly both should happen anyway.