Utilities have a considerable tax participation in municipal and state level governments. The infrastructure was definitely built with taxation, and there is a virtual monopoly of it.
Im not making an opinion about it being the best system or not, because i haven't looked at this topic at all, but its delusional to think there is no force in this application.
Just googling shows that for example, Florida has a mandate to be on the grid.
Everyday.
Think of it this way, people that don't want to use the service can't opt out for the tax loss incurred by the state running it.