But what about large governments? Japan has amazing internet service, and NTT is mostly private (with the government retaining only 1/3 ownership).

I would trust my county to deliver my fiber internet. All my government services work great. I literally marvel every time I visit our municipal dump, which is cleaner and mode efficient than my home country of Bangladesh. But I wouldn’t trust most of the other counties I’ve lived in before to do it (Baltimore, Wilmington DE, Chicago, etc.).