Those are good points, some of which can be mitigated with smart technology. For air conditioning homes, kick them on at timed intervals (or just traditional thermostat settings for times when nobody is home so the house doesn’t get extremely hot).
Agreed completely that the grid demand is very high between 4pm and 9pm. When you start adding electric cars to the mix, demand will soar (though that too should be done with smart tech so it doesn’t have to kick on until later in the evening - but it will still increase demand at times when no solar is being generated).
Decentralized is absolutely the way to go, but not the way TPTB have centrally planned it. It is less stupidity than corruption I fear. It makes perfect sense to put solar panels on buildings - as many as possible - to power individual homes and feed the neighborhood too as possible. To go out and law panels on 25 sq miles of empty desert is about as absurd as possible a method to use solar when it can be generated, delivered and stored directly to the places of demand. All you need is surface area and homes and industrial buildings have plenty of that.
High use places (hospitals, factories, office towers etc) would need even more creative solutions. And just throwing the switch from coal/gas to electric on X date in the future will work about as well as switching water sources on X date did for Flint Michigan.
Keep in mind that I have 64 solar panels for my 2,300 sq ft home. And it provides 80% of all the power I need year round (less in the winter, more in the summer). Now it's an all-electric home, and that includes charging our EV to drive 1,300 miles per month (the charging done at home, not counting when we charge it away from home on trips). Providing me with 80% of all of that ain't shabby -- but it's still a long way from 100%. And that's just for one family.
There's simply not enough roof space on most businesses to come close to 20% of their power need. Why should they bother going through all of that just to save 5% or 10% on their power bill?
Yeah you definitely want staged air conditioning. The government would be who decides what stage you are on. If you want to make sure nobody has enough energy put the government in charge of production. If you want your air conditioner to be on when it is cold outside, that is another great job for government. And if you want to stagger air conditioner controls and thermostats you will have to have government involved.