PC gaming is not here to stay. One day, someone, will finally do a cloud /saas streaming solution which works, which solves the latency and fidelity issues and which will be accepted and trusted by the masses.
Hopefully that will be a Valve solution. Not Nvidia, MS, Google or Sony.
From that moment on the client will not matter anymore and you will just stream it to your device and from there cast it to your big screen.
Hopefully I'm full of shit and this will never happen. But I'm afraid I'm not.
That device costs thousands of dollars. The os license fee is around 35-50. It barely even registers in the grand total. Add to that the well known MS management and reporting tools and everybody choses the MS variant. They know it, they can use it and the store staff can even do first line support themselves lowering the tco even more.
That's it.
Edit:typos