I have two points I think: there are more components than you are giving high COL areas credit for, and that even if high COL see some sort of exodus, this is not good for low cost of living areas.
I have been working remote for startups since 2019 and for whatever reasons, you could attribute this to low interest rates I suppose in your favor, things have gotten INSANELY more expensive. NYC, Boston, DC, Seattle, SF, LA, Miami I don't think they are getting any cheaper. These are Americas Elite Cities and thats going to command a demand that might seem to defy logic.
However I think people genuinely love living in these big HCOL cities. Otherwise it would defy all reason why they have been population centers for hundreds and hundreds of years. Take for instance Amsterdam; has Amsterdam gotten cheaper in the last 500 years?
To my second point, even if we are lucky and the money gets spread around a little bit what happens to the person working for 7$ an hour at the Hyvee in the Ozarks just because a small flurry of people from San Francisco and Seattle decided to settle there? What happens when he can't afford the property taxes on his paid off home anymore because a a random demand driven spike has increase the value of the properties around him to a point where he can't afford his property taxes anymore?
What happens when he can't afford his medical bills because of this? I've seen what happens and its a hunched over old dude outside of a tent on the streets of Seattle.
This isn't really the tech workers fault or the locals fault, but the fault of our government to account for inequality. Just something I've been thinking about. I just don't think that remote work is going to make life easier for anyone in the short term, except for the already spoiled white collar worker.