To be honest, my OP was a little hyperbolic. It's more like you'll be less able to demand a wage premium because you're willing/able to live in a high COL place. But you still have lots of other attributes/skills which are valuable.

I already live in a low COL location and successfully demand Bay Area salary. So obviously I don't see a problem with this. Most people all across the country will see no appreciable change here. The only people who need to be concerned are people who are unable to demand a high salary based on their attributes other than geography.