This is a nice rosy view of things, but it's just not accurate. They're de facto infrastructure builders, and for their efforts they want a monopoly on that infrastructure, with all the powers it comes with (e.g. favoring some traffic over others). The problem is that everybody long ago realized that infrastructure monopolies are a bad idea because they destroy both competition and infrastructure growth. It's why major roads aren't owned by private companies, it's why the electric company can't charge you more if they don't like the brand of your TV, and it's why public transportation services like trains and buses can't charge you more if you're partners.
Letting private businesses compete in various niche ways is fine as long as they are (1) actually private and (2) actually in a working free market. Telecoms in the U.S. are neither. They're so heavily subsidized and regulated that they function more as pseudo-government entities who should be entrusted with very serious business of maintaining public infrastructure. But they should definitely be prevented from rampantly discriminating against their customers to profit. The whole point of infrastructure is that it is a common public good, available to everyone equally without discrimination.