In most areas that have single-family houses, it is illegal to build 16-unit apartment buildings. In the places that most need more housing, this is the most true.
I guess I should've used a more realistic example (one home vs a duplex, or a 16-plex vs four single-family homes) but I really thought the point would be obvious. I guess not, so I'll try again.
You recognize that there are occasions when a developer has the option to build more density or less density on a specific piece of land, yes? I was using an exaggerated example (1 vs 16) to illustrate the more general concept of less-vs-more. I am arguing that, other things being equal, higher wealth inequality will lead to developers choosing to build less density, because an increase in wealth inequality implies that the rich have more to spend than the poor (relative to whatever previous period you're comparing to that had less wealth inequality).