Google made the same argument in this case but Epic responded by saying that impairing the competition is sufficient to describe the behavior as unlawful.

But Valve doesnt do anything to impair competition. Google owns and controls the operating system, require their store to be installed, and pay off other companies to be the default. Valve doesn’t do anything like that.

In fact Valve is pretty much the only company trying to promote a FOSS OS that no one controls.