I think it went like this:

• Windows 98 released: 95 successor, isn’t really useful until Second Edition. Relatively unstable.
• Windows 2000 released: NT4 successor, targeted for workstation use (not general use). Some hardware support from NT4 (not quite smooth). Driver (and application) problem solved as time goes on.
• Windows ME released: adds some features, too bad still based on 98. Even more unstable than 98.
• Windows XP released: can use most drivers from 2000 (guess why it’s easier to be accepted), and actually targeted for general use. Highly preferred since ME was crashier than ever and 98 is getting old – and XP is much stabler as it’s from NT line. And repeating, it enjoys drivers availability from 2000.
• …few years went on without any new Windows version release:
  • Most programs available assumed everyone is administrator
• Windows Vista released: architectural change. Most drivers broken, most applications assuming “user is administrator” broken in unfunny way (including WinRAR, Foxit Reader, etc).
• Most people stayed on Windows XP but most new applications are actually fixed to stop assuming “user is administrator”. Drivers for Vista kept coming up.
• Windows 7 released: most applications are fixed, drivers from Vista are usable. “It’s much better than Vista”. Everyone is happy.

In summary: without Windows 2000, Windows XP probably won’t succeed. In same spirit, without Windows Vista, Windows 7 probably won’t succeed. The latter would be much worse if it actually happens, though. And if you look closely, 2000 -> XP is 5.0 -> 5.1 and Vista -> 7 is 6.0 -> 6.1. See a pattern there?

In other news, Compiz’ alt-tab (and the switcher, etc) is still crappy as ever. Who cares about fancy animation. Give me non-crappy alt-tab please!