I'm also in New England but grew up in suburban Denver and I think it might well just be a matter of the houses and neighborhoods' having existed before anybody

I'm also in New England but grew up in suburban Denver and I think it might well just be a matter of the houses and neighborhoods' having existed before anybody got the bright idea to make HOAs. It's hard to enforce an HOA on owners who already have their houses. It's a different thing altogether when you're expanding into unbuilt territory.