It's part of the bargain: we recognize that these sorts of companies form monopolies[0], and in exchange for those monopolies, we impose regulation to keep them from engaging in the negative, anti-consumer practices often associated with running a monopoly.
We expect that if there were a competitive landscape, the companies that succeed would find a balance between profit and providing the services and quality that customers demand, but we don't have a competitive landscape, so we need to ensure that happens by other means.
We expect that if there were a competitive landscape, the companies that succeed would find a balance between profit and providing the services and quality that customers demand, but we don't have a competitive landscape, so we need to ensure that happens by other means.
[0] My take on why this is ok, and why we don't really want the proliferation of these sorts of companies: https://news.ycombinator.com/item?id=15858078