>ou don't have to spend too much time wondering, since its prima facia self-evident.
You should know: When you say something is self-evident, you will be called out on it.
>HOA's exist because they work out financially better than the alternatives.
Definitely not self-evident. I've talked to real estate agents who do not agree that it affects house values. My neighborhood has no HOA. Lots of non-ideal lawns her. One block south of us they do have an HOA. Very neat lawns, and houses all properly painted. Those houses do not sell for more.
Perhaps it does impact the price of the house, but I'd wager it is a miniscule effect compared to all other factors (size, neighborhood amenities, schools, etc).
I find that most people who make the claim about property values use it as a post-hoc justification to wanting to enforce a certain aesthetic on others.