Local governments encouraging them in order to shirk their responsibilities (e.g. they don’t have to maintain the street if it’s private), as @HubertManne mentioned, is also recently a thing.
Still, those reasons are both very new, and thus don’t apply to the vast majority of HOAs.
There’s actually a #3 that has become common in the last ~20 years: provide the developer with a continuing revenue stream via HOA fees.
Local governments encouraging them in order to shirk their responsibilities (e.g. they don’t have to maintain the street if it’s private), as @HubertManne mentioned, is also recently a thing.
Still, those reasons are both very new, and thus don’t apply to the vast majority of HOAs.