We’re evolving towards the status where airconditioning is no longer optional when building/renovating a house.

I have mixed feelings about measuring their wealth based on share prices because they couldn’t sell their shares without tanking the price, right?

Technically this is true, but remember that the wealthy can borrow money backed up by their stocks, so no: they couldn’t sell those stocks without tanking the price, but yes: they have access to even more money because of this.