Even a small (~10 home) development, of which we need hundreds of thousands, will require millions in financing. And as the development gets smaller and requires less financing, the economics get a bit worse due to ~fixed cost of land acquisition, development, and infrastructure/utilities.

> Many companies often lose money, due to incompetence or bad luck

One of those signs of incompetence or bad luck is building a bunch of new supply into a market with falling prices, in which case you will find yourself not among those with healthy margins ;)