Even in America, there are plenty of places that have municipal ISPs. But it has some... interesting political dynamics.
Basically, because people move out of cities that don't have good Internet connectivity, and it's unprofitable for private industry to serve rural America, rural America's towns and cities wound up just building their own ISPs. However, since a lot of these cities tend to be in blood-red states, a lot of these networks get kneecapped by state legislatures who are bought and paid for by cable companies worried that the government will subsidize Internet service into oblivion.
For example, in Utah we have a municipal fiber network, but because our state politicians are bought and paid for by Comcast, the UTOPIA[0] network is wholesale-only. That is, the towns in UTOPIA can lay the fiber, but they can't sell you Internet. At least, not without doing a shitton of accounting work to prevent subsidization by making sure they're accounting for costs that a fully private system would theoretically[1] incur. So, because of these stupid accounting rules, you have to buy Internet from someone else who is then paying UTOPIA for last-mile access, which makes it very difficult for UTOPIA to actually break even on their build-out. Other states have even more onerous laws[2] regarding municipal ISPs.
The thing about regulation is that it can either be constructed to improve competition and market freedom (i.e. antitrust) or it can be constructed to build moats around existing competitors. The state is the root of almost[3] all monopoly, after all. Additionally, it's difficult to write competent regulation without expert opinion; and if all the experts work for 2 companies, it's very easy for those companies to 'keep the story straight' and hoodwink the public. If you have a public option, then you can 'prove them wrong', so to speak.
[0] Utah Telecommunications OPen Infrastructure Agency.
For what it's worth, I'm not in the UTOPIA coverage area, but they did also have a Google Fiber buildout in my neighborhood. I jumped off Comcast almost immediately.
[1] To be clear here, almost no telecom last-mile is actually fully private, that's why Ronald "Fuck Antitrust" Reagan was willing to break up AT&T. This is just to make UTOPIA's life harder.
[2] https://www.baller.com/wp-content/uploads/BallerStokesLideSt...
[3] Strictly speaking, in a perfect ancap world of perfect competition with no aggression on homesteaded virgin land, you'd still see monopolies develop. Both because certain companies have value as infrastructure and because someone will break the whole 'no aggression' thing pretty damned quick and make themselves the state.