City-owned Internet services offer cheaper and more transparent pricing

I'm guessing "it depends" on the locality but in general there's nothing magical about being an entity that can sling cable around the town on poles. There are already typically two providers doing so (besides the electricity utility) : phone and cable tv. If you want to you can start a company and do it too, if you live by their rules, man. Rules include things like using qualified people to attach stuff to poles, be insured appropriately, other kinds of "government over-regulation" stuff, and of course that there be space available on said poles. In our very small town there's a retail store that has their own fiber between two of their locations. I suspect they contracted its installation to one of the regional fiber maintenance and installation companies. That's probably how you'd do it too unless you like owning bucket lift trucks and being on-call to come out and repair fiber when someone drives into a pole.

Now, in some cases the city has issued a "licence" to a provider to deliver some service city-wide (e.g. cable tv). That agreement might include some non-competition provisions, on the basis that said provider spent $$$ installing their system and is only willing to do that if they are guaranteed to not have competition. This might be viewed as "not allowing access to poles" even though it actually isn't.

And which federal entity will over see this? Considering it's a Communications service, perhaps a Federal Communications Commission?

We have one. Have you seen what they've been up to? What's the likelihood this policy would ever be enacted under the current administration?

And from there, this map: https://muninetworks.org/communitymap

might have something to do with hydro electric dams and cheap electricity, so they can subsidize the costs

(Just guessing)

I'm not sure how you arrived at "only Americans." How many countries offer a public ISP as an option to all of their people?

In news that will shock only Americans.. After regulations imposed by govt at all different levels (state, fed, municipal), it turns out the only ones capable of competing in such an environment are the ones who restricted and closed the market to competition in the first place..

ftfy