> and the common sense intuition that never occurs to people to turn out in favor of apartments they’re not going to live in

That ignores all the people who have other incentives to build.

Depending on the area you probably have about 10% of the people who have jobs that directly benefit from new construction (construction workers, plumbers, electricians etc…) or who are married to people who do. Then you have all the people who work or own businesses in sectors that indirectly benefit from new construction or directly benefit from increased density.

In my town of 8k people, I’ve seen 30 people from those groups show up in support of a new sub division vs half a dozen against.