Hong Kong was (probably still is for now) a world class city for the rich and the free and now is on path to become a hell-hole for both.
Cities swing through a pendulum of up and down. SF might be going to ruins but it'll be back. It might have to reach rock-bottom first before re-inventing itself though.
That said, the city does not have visible homeless or crime problems of most large US cities, partly because you can legally get a coffin for $300/month.
Why not? Are there support systems to give people shelter and reduce the need for crimes of desperation?
> Tokyo could be the rare example of a once expensive city that successfully managed the difficult political process of removing planning restrictions in order to achieve affordable housing.
They didn't achieve affordable housing as a result of a clean slate. In fact housing in Tokyo was insanely expensive during the 80s. It wasn't until zoning restrictions were changed in the 90s that prices came back down. It's about the laws, not about having to contend with old buildings.