I can think of many neighborhoods that have seen investment from groups other than traditional developers, including from individual homeowners. Take, for example, Cabbagetown in Toronto. There was never a top-down developer moment. It was individuals who saw beauty (and also opportunity) at a time when others were scared of the area. Is that acceptable? Perhaps more importantly, did these people wear black suits?
The other missing piece is the fact that desirable urban neighborhoods are, today, in incredibly short supply. During the reign of Robert Moses, Jane Jacobs had a view of cities that was in opposition to the planning zeitgeist of the time. But over time, she went from controversial to enlightened, and alongside this we saw a return to cities.
Combined with strict land use policies, this rising demand for Jacobian-style neighborhoods has meant that many/most dense urban centers operate with a perpetual housing supply deficit. There's not enough cool urban housing to go around. Add in the current low interest rate environment, and you then have even more money searching for that perfect home in the West Village. That tends to do things to prices.