They're in a weird place with regard to antitrust: they can, to a degree, promote their own software, since it's their own software. But they can't limit what

They're in a weird place with regard to antitrust: they can, to a degree, promote their own software, since it's their own software. But they can't limit what an OEM does because they've already sold their product to OEMs and the business is "complete", as far as US law goes.