I agree that the antitrust lawsuit was significant! However, I don't think this conflicts with Graham's argument.

If Microsoft had been free to act anti-competitively, it could probably have blocked the emergence of Google and the web, and possibly Apple.

The antitrust issues were a small piece of a much larger puzzle. Microsoft wasn't dead because of anti-trust issues. They were dead because Ballmer took them in the wrong direction. He made lots of money, but killed the culture of Microsoft.

If they wouldn't have had the eye of regulators on them they could have financially buried a bunch of startups. But that didn't make them turn their products into garbage. There were many issues.