> the AT&T break up set American technology back by decades

Actually it helped the telecom industry prosper because of independent innovation. The innovators became separate from the utilizers. This allowed both sides of the industry to mature into full three-part businesses.

I will give you that it killed other shiny unprofitable technologies. But imagine if that same thing happened with IBM? Where would IBM be today? How many old tech would be shown the door? How many companies would be buying the latest and greatest innovations?