I think the bad pat about windows 7 is that they put out Windows 8 way too quickly.
There are a lot of people that would be OK with being dragged into upgrading if Windows 7 was an easily available option. Bu now, MS is pushing manufacturers into pre-installing 8, which is NOT a good transition path from XP as Windows 7 was.
The problem was that it was a complete pivot on an operating system people finally saw as the true successor to Windows XP. It's what Vista should have been, a nice polished and professional OS that generally was out of your face, yet extremely useful. Then there was windows 8, not horrible, there were some under the hood improvements but the horrible hybrid metro/desktop interaction alienated the desktop market and no clear incentive to upgrade.
The bad part about every Windows since Windows 2000 is that it didn't really offer any new value. A bit more bling in the GUI, yes, and security, yes, but fundamentally Windows 2000 is just as good as Windows 7 from a productivity standpoint. So a lot of people saw that, and decided to just stay with XP until they are forced to do something different.