>Their government paid to build a nation–wide fiber network
So did we. The last step is nationalizing that network and finishing the build-out in-house.
When we paid for national broadband access here in the US, it was not for fiber to the home. It was for DSL. Worse, the FCC measured coverage not by service address as it does today, but by census district. The phone companies merely had to assert that they could provide service to an address in the district and the FCC would count the whole district as covered. The districts aren’t very big, so in dense areas that was not a bad estimation. In less dense areas it was just a giant loophole. They could provide service to one house on the edge of the district and not bother with the hundreds of homes miles away out in the countryside. Officially we got exactly what we paid for.
As you say we could still nationalize these fiber networks and stitch them together into a real national network. Of course they don’t all use exactly the same technology, and it would be a huge political fight, but in principle I could see a government agency gradually buying networks from the ISPs and integrating them. Of course you know that if Trump proposes it then the Democrats will immediately oppose it on the general principle that Trump proposed it.
Municipal fiber is not outlawed here in Oregon, so there are quite a few municipal networks here. But they are not expanding as fast as even a single ISP like Ziply Fiber. None of them have expanded beyond their small town to serve unincorporated areas near by. All of them are funded more by taxes than by subscribers.