Well, wait a minute, part of that was that in the old days, we were on the steep end of the curve on operating systems and office suites. People snapped up the next version in the (sometimes vain) hope that it would fix significant bugs in the old, or add much needed capabilities, or support new PC data connection types and hardware, which were also on the steeper end of the curve. Windows 3.1 was a huge update from Dos. Window 95 was a huge update from 3.1. Win98SE gave us USB support. Windows 2000 gave us a much more stable kernel. And so forth.
I submit that right around Windows 2000 / Office 2000, the curve started flattening out. We reached the point of diminishing returns. Windows XP was a sweet spot -- stable enough for daily use, compatible enough to run almost anything, with a rich enough collection of peripherals. (I submit that Office 2000 is good enough for most people -- I still use it now, on Win7.)
Windows 7 was attractive to me on my main workststion because the 64 bit version was very stable and for my work I need large amounts of memory. But for most people, 32 bit XP is good enough. Wife and daughter's machines still run XP, they're fine with it. Daughter has a touch screen ASUS running Win8, but I don't think she's powered it up in months. She doesn't like Win8, and XP meets her needs.
At my work, we are just now pushing Win7 (not not NOT Win8) on the XP users, and there is huge resistance. Because XP is good enough, and the users just want to get work done. They don't want to play with operating systems. I've said this before --- the OS is not the application. The OS loads applications.
One could say a similar thing about the PC industry as a whole. There was a time when most of us hungered for the next faster chip. But generic PCs have gotten fast enough that most users couldn't take full advantage of them. This reduces the need to pick up a new machine at every iteration. We're on the flat end of the curve.
Microsoft's mistake was in believing that this rush to buy whatever new iteration they happen to crap out would continue forever. $$PROFIT. They couldn't see that the knee of the curve was approaching. So now they're struggling to find other ways to stay relevant.
Parenthetically, I wasn't aware that the going was in any way good for Windows 8.