[pas]

That'd be the illegal part of being a monopoly. The antitrust laws work by restricting (penalizing) monopolies from abusing their market position/dominance.

Basically, it's not a problem if you happen to be the best in computers. But it's a big no-no to try to force resellers into exclusive contracts and so on. (If you continue to just buy up newcomers to the market that's not a problem, after all investors can just keep funding new competitors and you have to waste money.)

But of course this is a very difficult problem at the intersection of economics, politics, law and sociology.