What do you think innovators will feel when they see the government breaking up a private company? Do you think they’ll be more or less motivated to create one to meet the same fate down the road in the unlikely case of success, after immeasurable difficulties and struggle?
Ever heard of second order effects and chilling effect of regulation?
The next company to devise new ways to outwit antitrust action via loophole legalities devised by their armies of lawyers funded by all of the money they've made operating in the competitive space cleared out by antitrust action.
Startups do not have to worry about such issues until they themselves become incumbents, which they do after the previous incumbents were brought low by antitrust action.
Seems to have worked out okay in tech, because we have the benefit of technological progress. WinTel dominance is moot because smartphone is the name of the game, and MS was unable to execute. The Mac and Linux were also able to catch up in the meantime, even though Windows is still numerically dominant on desktop.