I wouldn't put Honk Kong in that list though as much as I like the people and the city. I've been a few times and the infrastructure looks like it's falling apart. Electricity wires are hanging haphazardly, alleyways are dirty, and most facades of buildings are straight out of the third-world. The contrast between high-end boutiques interspaced with tiny mom-and-pop shops selling second hand stuff is a little surreal.

What you described is the exact impression I got when I first travelled to New York :)

"Is it supposed to be this dirty?"

Come visit downtown San Francisco :D

I go fairly frequently these days and am not surprised by much any more ;)

More developed mostly means ‘newer.’

These places will also have to figure out what it means to keep infrastructure refreshed in 50 years. It is always a struggle..

Many places in Europe run way older infrastructure yet feel more developed than top tier cities in the US, so I don't think that's the reason.