I live in Sweden where there is a national plan for rolling out broadband internet throughout the country until 2025 [0].

In Stockholm the physical infrastructure is rolled out by the municipality through Stokab [1] exactly to avoid this issue, the physical infrastructure, which is the most expensive and least competitive part of the deal, is public while leasing it out and providing access to the last mile customers is done through private companies. It seems to work pretty well so far.

[0] https://www.government.se/496173/contentassets/afe9f1cfeaac4...

[1] https://www.stokab.se/Documents/Stockholms%20Stokab%20-%20A%...