That's why Microsoft. Because even the people who complain their stuff is flaky still wish all the other companies had emergency response technical teams that were half as good as Microsoft at getting systems back up and running.
Same argument for Mainframes. IBM would fly people out to us when there was an emergency. All this says is that when you can afford it the right hand side of the curve responds very well. Which means you can afford to hire know-nothings (no offense) for your day-to-day work.
I don't think this model fits most businesses. In which case Linux might make more sense. A bright person who works in a Linux environment has far more power to act in an emergency than someone in a Windows environment.
w.r.t Contracts, I've never seen an exclusive one like the OP mentions but I do notice that MS tends to bundle stuff in their site licenses. Our Sharepoint project was begat due to the fact that it was "free".