The government could do it that way, but you have to trust them to do it correctly the first time. Because those government run utilities don't run on ten year upgrade schedules they run on 100year upgrade schedules. When homes and apartments are connected to water and power networks they never get upgraded.

A national internet service designed in 1999 might just be ADSL for everyone.

There is a lot of talk about how great municipal fiber is, but a town near me did it over ten years ago. Took out 30 year bonds to build a 10mbit up / 10mbit down system that's pretty expensive.

You only have to look at telecom regulation in the first place. After deregulation prices dropped and investment in advances started up again. Tons of money was invested into wireless. But AT&T wasn't pushing that forward at the time.

You have to consider political issues. Voters hate "rate increases" for power, water, and electricity. Proposals to jack up rates to build a FttH system to every home I the country would be shot down.

And if you mean true government ownership and operation of the network there are privacy and censorship issues. In the USA the government is allowed to censor government airwaves but not cable networks. I'd worry that censorship attempts would be tried on an government owned network.