But should they have to? I would argue that they should
Intel, or other SoC vendors if they start integrating Atom, will happily provide security modules like ARM does and list it as a bullet point on their spec sheets. There is nothing about x86 that makes it immune to lockdown and as you said, Intel does not care who wins the OS wars so long as it runs on their chip.
I think you miss the point, namely pointing out that no matter what you do, MS can throw tacks in your path at which point you fix the flat or you diverge from the MS path.
it is not where Windows is going but where it has been.