The supply may not explode - maybe most talent was already tilted towards those expensive areas since that's where so many jobs were - but for any given employe

The supply may not explode - maybe most talent was already tilted towards those expensive areas since that's where so many jobs were - but for any given employer in a given city, today's supply is a lower bound for their supply if they accept remote workers. It can only go up. There's a potential scenario of now "company in cheap city X is willing to pay for SF talent, but couldn't convince them to relocate before, but can now hire them remote" that would also push up demand for top talent, but it seems much more likely to me that demand for top talent stays about the same while supply increases at least a small amount, which would push down wages.