You're claiming that your internal IT department does better QA on Windows than Microsoft does. That's amazing. Do you have evidence to support this? How many major bugs do you report upstream? What's your QA system like? Can you confirm that your test suite checks upgrades using Known Folder Redirection when the default path is still in use?
I find it awfully hard to believe that you're arguing for using Windows on the basis of TCO, while on the other hand apparently have (and need) a QA department and test protocol that exceeds Microsoft's, and are willing to pay Microsoft to produce patches for an old OS just for you.
You've got 100,000 systems in a highly constrained environment. You pay for the licenses, and to run your own upgrade servers, and to do your own QA on their software, and to get patches for it, and you can't even run the current version because you think it's not "sane". I'm sure there must be external constraints you're not telling us, because this doesn't sound rational.
I find it awfully hard to believe that you're arguing for using Windows on the basis of TCO, while on the other hand apparently have (and need) a QA department and test protocol that exceeds Microsoft's, and are willing to pay Microsoft to produce patches for an old OS just for you.
You've got 100,000 systems in a highly constrained environment. You pay for the licenses, and to run your own upgrade servers, and to do your own QA on their software, and to get patches for it, and you can't even run the current version because you think it's not "sane". I'm sure there must be external constraints you're not telling us, because this doesn't sound rational.