Counter-anecdote: I've only had AT&T and Time Warner Cable (now "Spectrum") and I would rather deal with any government agency than either of those two. Specifically I would rate my water+sewer and electricity 5/5 stars while I would rate TWC and AT&T something close to negative infinity.
Are you imagining a monolithic federal-level agency? Most municipal broadband schemes are run like small non-profit businesses that just happen to be publicly/community owned.
Let me put it this way: Comcast is the only reason why a lot of the US doesn't have gigabit internet at cheap prices.