Steam

I think the whole "monopoly bad" notion is a bit off. You start opposing monopolies, but then people realized that duopolies are also bad, and next thing you know we talk about triopolies and centiopolies and whatnot.

So I think the actual number is not the thing that matters, and instead the thing we should be worrying about is cartels.

The defining feature of a cartel is the ruthless action it takes to kill competition. The monopolies everyone are so mad about are cartels of single companies, but the bad thing about them is their cartellic behavior - not the fact they are along in the market.

Steam is not a cartel.