The marketplace would ensure a car that onl ran gas from one company would not sell. There are plenty of companies building systems that will run Linux or the operating system you chose. If that was a consumer demand then those companies would grow. No need for the Gvt to choose winners or control the product line.
I already own several, why should I have to buy a new computer to get Linux? No... These I have are MINE not theirs and it should be easy for me to change the operating system on MINE if I want.