> My dude, that is a circle from Poughkeepsie to the tip of Long Island. Forget one-story single-family housing, there is farmland in that circle.

That's kind of the point. Notice that housing demand is recursive.

The area you're talking about is NYC metro. If you draw a 100 mile radius around Manhattan then Poughkeepsie is inside it. Is someone going to live in Poughkeepsie and commute to Manhattan? Probably not. Is someone going to live in Poughkeepsie and commute in the direction of Manhattan? Absolutely. Which in turn recursively alleviates housing pressure in that direction. More housing in Poughkeepsie frees up existing housing in Peekskill, more availability in Peekskill frees up existing housing in Yonkers, lots of people are willing to commute from Yonkers to Manhattan.

And both "100 miles" and the NYC metro area (the highest population density metro area in the US) are far extremes. The point is that even that would improve affordability if it was the only option. Meanwhile in reality there are single family homes that could be 5 story buildings in Yonkers, if it wasn't prohibited by zoning.

> If people were willing and able to commute that distance you could easily quintuple the housing stock in that area building nothing but one story SFH.

If you actually did that, would housing affordability improve? Yes it would. It's in fact what's slowly happening on its own when the better alternatives are banned; it's why housing in Manhattan isn't twice what it is now. But that's sprawl. Sprawl sucks. People pay less for housing but have 60 minute commutes. Why do that by adding far away single family homes instead of adding medium-height buildings closer to where people work?