Not true at all.
Solar power is borderline reasonable for SoCal.
Requires approx 50-70% investment credit to break even.
As regulations such as this take effect, cost of energy goes up - break even for solar comes down.
Solar power in SW US is a cost/benefit problem - not a technical feasibility problem. Except for the giant batteries they will need when the sun goes down - but again - peak solar matches peak AC demand - so SoCal is not that weird a place for Solar.
Summary - it isn’t stupid - just innefficient.
Although I’ve seen some pretty interesting research that could get solar to the point of natural gas in 10 to 15 years.