By the way large investment, low per-customer income means that, even if ISPs had gone there without government incentives - they would STILL have been a monopoly.
Because a large investment and low sales margine is the definition of a natural monopoly. It is NEVER worth it for a competitor to appear when those conditions hold - because the other company always has the advantage of having made part of their investment back already. Such cases the market can ONLY EVER be a monopoly.

So making it a government monopoly actually reduces the harm of the monopoly - because that means you can at least make some rules to limit how much it would be abused.
Chances are- in many places nothing would exist, and the others - there would be a monopoly just as there is now.