It may be the case that expensive cities are killing creativity, but I suspect the real culprit is the belief that you have to live in a certain sort of place in order to create.
If you want to have time to make your art, it helps to live somewhere that offers low overhead. Cheap rent, or — imagine it! — an affordable mortgage, in a place that’s reasonably well-tended and feels safe. Because chances are it isn’t the city that’s killing your creativity, it’s the amount of money it costs to live there and the amount of time you have to spend acquiring that money. Scarcity — insufficient time, inadequate funds — is the real creativity-killer.
Maybe going home to your “dying” hometown — or some reasonable facsimile thereof — will serve your creativity in ways you can’t imagine from where you are right now.