For the same reason I'm not still running 7...because you can't actually stay on one version forever. I'm going to put the whole Linux thing aside because... Yeah, that's a topic of its own and I think anyone with half a mind knows the reasons why Linux isn't everyone's first choice.

But at some point Win 10 will reach EOL and will stop receiving updates. It'll stop receiving new versions of DirectX etc. People will stop making drivers for it. Software will start requiring things in newer versions of Windows, etc. The list goes on, but inevitably you have to update.

Luckily with Windows, you can usually skip one full release, but you can't really make it past 2. Hence why I said 12. Am I crazy about the way 12 is shaping out? No. But you'd be crazy to think that you can just remain on 10 forever so I'm being realistic.

Also, Windows is well known to have a shitty even/odd cycle where every other release sucks and the alternating ones are less bad. So hopefully 12 will be the same. For example, 95 was really good, 98 was meh, XP was fantastic, ME/2000 are kind of a joke, Vista sucked, 7 was good enough, 8 was miserable, 10 was okay, 11 is awful... So if the pattern continues, 12 should be better than 11 at least.

I didn't think this actually needed an answer but... Maybe I'm getting old and am too used to Microsofts cycles. Also, my point was "this isn't a problem till 12" meaning, I'm not touching 11 so it doesn't even matter till I start considering 12. Never said I was definitively doing it.