At its core, YIMBY is about what de Tocqueville called “self interest, rightly understood.” It is about folks who have access to a resource deciding not to protect it and make it scarce, but instead opening it up to a broader community. It is about battling selfishness in our public policy, and believing in a positive-sum, abundant view of the future.
Misha Chellam on YIMBYism broadly construed:
https://modernpower.substack.com/p/building-the-yimby-faction