I think you mean perceived detriment. Even a very large corporation will benefit directly only a tiny segment of the population--a segment motivated by greed. The government should regulate so that society as whole benefits over the longer term.
This thread seems to be dominated by the pro Windows crowd. For what it is worth, I work in a Mac dominated science department at a University with an IT support unit that does not support Apple and has lobbied actively to discourage any use of Apple products. Two weeks ago IT began exploring ways to begin Apple support. What caused the reversal in policy? Over the the past decade Apple usage has increased in all departments, and the voice demanding Mac support has increased in volume. Last week the University revealed that 50% of the access to the campus-wide wireless was from Apple devices. All this happened in the face of active opposition from central IT, which is a pretty strong statement of the Mac platform succeeding on merit.
Ten years of consulting on university IT issues and working in the only Mac majority department at the time, demonstrated to me that Mac support is much easier than Windows. What is more difficult, is to support Macs exactly the same as Windows, which is what Windows support staff feel compelled to do. What Windows support staff mostly fail to recognize is that Macs don't need the wild support gymnastics the Windows requires.
Theneed to run a gatekeeper (Antivirus software) to protect OS is an admission the underlying OS is so hopelessly screwed up that it can never be fixed. I realize that there are circumstances where Windows is the only recourse, but why choose to use that mess where it is not necessary?
One additional comment: Windows software controlling instrumentation has also been mentioned in several comments. Using this implementation as a case for teaching Windows is a red herring. Much of this software has been ported from Unix, uses very eccentric UI elements (paragons of poor design and bad programming) and mostly freezes the OS version it was written on, because OS updates will break it. Our university IT support won't touch these computers. We had one very expensive analytical machine networked because the manufacturer did remote online support. That machine got a Windows virus and was down for two weeks; it has never been networked again.