The vagaries of American politics allow for failure and then bailout as a mechanism for these sorts of situations but I think we can see the writing on the wall. 50k residents at an average million dollars a resident is $50 b so it is not quite possible to have a buyout so I see why we just allow for the decline.
But any more we allow for the place to be inhabited, the greater the risk. Otherwise it’s just an incredibly regressive use of our resources: taxing a lot of working age people in the more urbanized areas to fund wealthy retirees in the forest.
The current tide of California politics favors that and we can do it so long as our economic productivity is powered by tech but a time will come after and it’s better now to do this than after when we will find ourselves unable to sustain productive capacity.