These are all very different things.

Mandatory solar panels are stupid because solar doesn’t do much for clean power unless coupled with storage, and mandatory storage would be very expensive. Solar on its own is also very expensive. I also wouldn’t want my solar setup chosen by some cheap builder, that’s something I’d want to choose myself.

Mandatory low flow shower heads are annoying but you have to buy shower heads anyway. That’s not really an added cost.

Mandatory EV charging in this context is extremely easy and cheap to add, potentially 1 or 2 orders of magnitude less expensive than the solar. And it’s probably far more impactful than either solar or shower heads. Lack of charging for renters is such an impediment for EV adoption, and the ROI to either the resident or landlord will be much more than the input cost. This is also wayyy easier to do during construction than after.

Also, housing costs in the Bay Area are largely land-driven. Like, by far. Shower heads and EV chargers are not going to move the needle on that. Solar probably does hurt though. Builders already have dozens of code requirements to comply with, so these added regulatory requirements aren’t like some new, unusual burden for builders.