Well, how fine grained do we need to get? A police force with 5 officers is pretty fine. In this case law enforcement is being taken over by the county (of which there are 254 in Texas) so its still pretty local.
As always: it depends. There are many municipalities throughout the US that are content with (or can only afford) county-level enforcement. If their residents want something more localized, they need to do what it takes to create that.
In this case, what’s happened is fine. Leaving it up to local residents and their local government to form a new trustworthy enforcement agency is fine. Leaving it up to them to not do that is also fine.
You see it with home owners associations as well.
Sure. But I’d default to the locals’ preferences in the absence of it.
Fun fact: Texas's counties range in population from ~5.1 million (Harris — Houston) to less than 500 (Loving, King, Kenedy [sic])