The breakup of the Bell System was a huge failure. When they were separate they never actually tried to compete with each other and then they just bought each other back up again.

What actually created competition for the telephone network was the internet. Competition from cable and satellite and cellular.

That's what you need. Something similar but not exactly the same, so they can each carve out a niche and provide a backstop against the most flagrant abuses but they aren't in such direct competition that they're more inclined to cooperate than compete. So that you have companies who can make choices knowing that their position is different than their competitors and the competitor can't just mirror their action to neutralize its competitive advantage, which otherwise removes any incentive to be the first to engage in pro-consumer behavior.