Visited SF in the mid 90s, then again about 10 years ago, and the decline was real back then. Tents on the same streets we'd walked as tourists 20 years earlier. I can say the same with Paris as well. New York, not so much, actually.

Living in London I don't notice the day to day differences here, but I would imagine others on here will say the same about London. It seems 'the West' has a general problem.