I think you ignore how much the telecom market reshaped itself in the meantime. Pre-breakup AT&T had complete market power over what technologies would or would not get deployed. The use of landlines has plummeted, to be replaced by cell phones. Today the average consumer has significantly greater choice when it comes to carriers, even if many of the usual suspects are still in the game. I question whether the breathing room would have existed in the market without the breakup. If you have an innovative startup idea in a space, and you have exactly one customer to sell to, you have a major uphill battle.