The difference between these and the internet is right of way and externalities. That is, the government is involved in roads and sewers because (1) you can't have a road network in most places without the ability to forcibly purchase small strips of land from lots of people and (2) until recently, there was no efficient way to charge usage fees in a reasonable way. The internet doesn't really have that problem: charging is quite simple and the flexibility of routing means we're not nearly so beholden to any one set of property owners.

Now, I think there might be a case made for making last mile internet either municipally run or a heavily regulated business in the same way that water/power/sewer service in cities is, but that's a very different argument.