It's honestly fascinating to watch unzoned Houston continue to incrementally density in the way that basically every other city did...before they adopted zoning. https://twitter.com/HeikoPierre/status/1389982610244440070

Like even in any other Sun Belt city, these detached townhouses would only be allowed as-of-right in a small sliver of the city, and would be a huge permitting ordeal everywhere else. In Houston they're legal as-of-right citywide. No deed restrictions? Here's your permit.

You build a house. Decades later, when prices go up, you divide that house up into a few more houses. Decades later, when prices go up, you buy up those houses and build an apartment building. It ain't complicated, just the way cities worked for pretty much all of human history.