They're generally unsustainable. Having a reputation means a deviation from the norm. Once their reputation is big enough, the number of newcomers to the culture will outstrips the ability for the culture to assimilate them.

Sustainability in the face of that requires whatever the culture is centered around to be the kind of thing that can both put up a facade that serve casuals and angry neighbors, while simultaneously maintaining an environment for the core that built it to retain momentum. And circumstance might just make that impossible.

There's a piece that covers this pretty well:

https://meaningness.com/geeks-mops-sociopaths

Last posted on HN 2 months ago:

https://news.ycombinator.com/item?id=17433487

That's a bit of a reduction. More like 'Any neighborhood in a world class city with a reputation ...' Milwaukee, Minneapolis, Kansas City could develop cool areas, but probably won't be overrun by AirBnB tourists.