>And then, after that comes a revolution in cities. Walkable, safe and cheap places with good internet have a lot to gain (e.g. Portugal, Thailand). Unsafe or expensive cities have a lot to loose (e.g. San Francisco).

This is somewhat wishful thinking: most companies cannot have employees that live outside their country. These workers instead need to become consultants, and contract to the client companies. Employing someone overseas is not easy at all, and most companies just aren't set up to do it. There is a new industry of companies that specialize in "employing" digital nomads, and then contracting their services to their employers back in the other country, but of course this adds extra cost to the client. For US-based remote jobs, they usually plainly say "US residents only" to avoid these hassles.