re: Rich and famous (as well as the middle class) are fleeing Los Angeles in droves

Death spiral could be looming for some of these urban areas. New roads, sewer lines, rail etc require municipalities to issue bonds to pay for them. That is debt. Municipalities levy taxes to pay that bond note.
Money leaves but the debt still needs to be paid.

Municipalities are left to find ways to pay that debt so they generally raise taxes on those that are left behind and that is the final flush that sends the remaining money for the hills.

Sometimes it takes tragic events to reveal truth.

In this case a Pandemic revealed that huge Urban settings are not necessary for commerce to transpire. Office space is not always needed.
High rents and high taxes don’t attract people. They follow people.

If you are invested in any municipal bonds, be cautious.