Brownstone neighborhoods stress these numbers even further (e.g. much of "hot" Brooklyn). These consist largely of 19th century buildings. And even the "modern

Brownstone neighborhoods stress these numbers even further (e.g. much of "hot" Brooklyn). These consist largely of 19th century buildings. And even the "modern" apartment buildings are 1920s, 1930s, etc. These are also precisely the neighborhoods that zone-limit modern construction to avoid compromising their character. So you have a bunch of old buildings that need serious maintenance, sometimes by firms with specialized and otherwise outdated skill sets (e.g. stoop rebuilding and iron fence work). Many of these neighborhoods are also in historic districts, meaning they're landmark-protected to preserve traditional architectural character. Brooklyn Heights is a prime example. Essentially the whole neighborhood is one big historic district. The housing stock is ancient. And it's a highly desirable neighborhood. Maintenance fees can easily waver between $1,000 and $2,000. There are very few modern condos (which basically avoid these problems). So their very scarcity inflates their purchase prices. All in all you get a very difficult place to live in and own property.