I'm desperately trying to think of an OS vendor that supports and OS for as long as Microsoft. None of the Unix vendors I can think of (in fact, from next year, the only supported version of Solaris will be the current one, which is piss poor, but what you expect from Oracle). None of the Enterprise Linux vendors (and the non Enterprise ones tend to be only the current version), OS X (but then Apple are a law unto themselves), then you're in the niche ones.
For all their faults, MS do support their stuff for ages, and their support is better than most.
My issue is that they make it impossible for ME to support it. Clearly, no manufacturer will have significant support for a mainstream product that old but, when we're talking about a system that was designed to do a job, accepted and put into service the "patch tuesday" type of support is the last thing I want anyway (and I've never managed to elicit any other useful type of support from M$).
It'll most likely be in a controlled environment where no changes that I can't account for are made (so, M$ patches can get right out of there!). Also, nobody uses it in an internet-facing role or to surf dodgy porn sites (in theory - I sometimes wonder), so that type of "support" is not especially useful.
My issue is that I can't legally sell it any more, or move the customer onto new hardware when it wears out, I can't legally get the development tools to support them any more, etc...
But.. that's a fairly niche application for which a consumer OS is being used, so not really surprising.
On a wider note, M$ have their work cut out to avoid being the next Nokia, IMHO, and they need to undo a lot of the bad in Windows 8 this time to achieve that. They bleat about having one "experience" on all devices, but the truth is that they have 3 incompatible "experiences". A crippled smartphone "experience" on a desktop machine, a crippled desktop "experience" on a smartphone and a third bastardisation comprising the worst bits of the other two on a tablet.