DNS/TCP is decentralized, and mostly operated by private companies, so arguably it's already privatized.

With TCP I agree. On DNS I wish we actually used classes so we could have multiple separate hierarchies, ofc URL design might be needed to be changed slightly.

This is not what gp described. Why don’t you provide an example of nationalized industry performing well?

I think you would agree that there aren't very many nationalized industries other than weapon systems research/development ("weapons" as in cruise missiles, fighter jets, air craft carriers, etc.) I think you would also agree that the on-paper-private companies that do this work are effectively nationalized would perform much worse if they were selling to citizens rather than nations.

As far as services (rather than industries), those that I mentioned are perfect examples of nationalized (or at least "shared" as opposed to owned by a single company) services that perform well: Highways, USPS, TCP/IP, DNS, SMTP. Though, I do admit that despite being built on publicly developed shared underlying technology, the actual deployment of DNS services or of devices that use TCP/IP or similar technologies is done by private companies.

This is also sort of adjacent to the debate of whether or not broadband access should be considered a utility and how utilities should be delivered.

In Europe most passenger railway companies are nationalised (or at least heavily controlled by state owned entities), and rail transport in Europe is arguably much better than in the US.

...and definitely not say, higher population density and/or government policy.

Maybe if you don't include deserts and Alaska in the density calculations you would get comparable numbers.

- Why don't big american cities have trolleybus?

- Because density , imagine putting those buses in the desert, would be stupid

- But why not put the infrastracuture starting from high density areas ?

- You are making sense now, let me find other excuse ... it is because culture/freedom/short history/ the constitution , the yellow party

- I don't have time to logicaly analize all those excuses, next time maybe

ralway is a natural monopoly

Healthcare usually does quite well. Terrestrial TV and electric grids made sense. Water supply and treatment aren't too horrible usually either.

natural monopolies, except some kind of health services

1) monopolies (also gov.) need to be broken or collectivazed for obvious reasons.

2) The government cant play the enterpreneurship game, except extremely fringe cases,