I totally agree with 'Bugaw's post here.
If I wanted to create a conspiracy theory, I would easily theorize that Microsoft has been paying off publishers to sabotage the PC builds of many AAA titles over the years.
But here is the thing - it would probably never have been done Intentionally.
Rather, the persuasion and financial pressure on the team to invest heavily in the technically-inferior build (the XBox build) puts such a resource strain on the team, that as anyone working in development knows, these resources have to be taken from somewhere, all this extra work cannot appear out of thin air.
What we end up experiencing as customers, especially PC customers, is something I have posted about couple times, 'here and there', since around 2007:
By Porting titles and doing multi-platform development, the overall product quality usually suffers, but the publisher gets to sell the title Three Times Over, rather than once. We as customers pay, in lost quality, so they can make more money. Fair? No way.