A huge portion of northern, eastern and southern queens, eastern brooklyn, and staten island is more than a 10 minute walk from the subway. I live in Queens and am a 40 minute bus ride from the nearest subway station. Swaths of brooklyn are the same.

Here's a map showing the tiny portion of Queens in walking distance of subways. https://cwhong.carto.com/viz/6dfca01c-47e5-11e6-9fd3-0ee66e2.... And yes, it's almost all residential zoned, filled brick to brick with houses and apartments.

Based on this density map (https://www.google.com/search?q=pppulation+densoty+map+nyc&o...) I'd peg it at 35% of the city's pop.

There are a fair amount of large housing developments outside of a 10-12 minute walk to a subway station. Co-Op city in the Bronx is huge (and according to Wikipedia, has 46K residents), LeFrak City in Queens is mostly out of that boundary and, the one on Pennsylvania Ave in Canarsie (whose name escapes me at the moment) are all large developments without easy subway access. You could probably also includes parts of Stuy Town/Peter Cooper Village and those Union Sponsored Mitchell-Lama towers in the LES as being farther than 10 minutes from a subway.

The map I see is this: https://imgur.com/h74uIJB I'd say there's a pretty large land area not within 10 minutes of a subway station.

Unless what you're trying to say is "places that don't have the public transport to support high-density housing don't have high density housing" - if that's what you're saying, I agree with you!