That doesn't seem like an adequate explanation. An HOA that only existed to maintain the stormwater plan and just collected small dues to maintain it would be almost completely unrecognizable compared to how actual HOAs function. Come to think of it, even my standard explanation of HOAs being prevalent because local government use them as a backdoor way to increase property taxes is inadequate, since an HOA that just maintains the roads and parks would also be pretty unrecognizable.

Maybe these explain why HOAs exist, but not why HOAs almost always have a big tangle of rules on top. Is there some regulation that explains that aspect?