The problem that could occur is: Right now Microsoft doesn’t care about Linux or competitors, every OEM has to buy a Windows key anyways regardless. If SteamOS actually becomes a shippable option, Microsoft’s cavalier attitude is going to change quickly, and a lot sooner than it will take them to get an Xbox Handheld out the door.
Why would an OEM need to buy a Windows license if the customer has no interest in using Windows?
It’s in their licensing, and how MS-DOS became the de facto operating system of early PCs. If you want to license Windows, you have to pay for every unit you sell - not just units with Windows pre-installed, but every unit.
Embrace, extend, and extinguish Microsoft’s gonna do what it does.