Microsoft seems to push the envelope with every other version. These versions are often not quite finished and do indeed push new changes
Win 98 to 2000 (I will ignore ME version, everyone else did) (Nothing really wrong with 2000 but many places skipped from 98 to XP) But who really needs an NT core and possible 64 bit processing?
Win 2000 to XP: despite the above article, it seemed to go smoother.
XP to Vista (or was that Beta Win 7?) Networking really needed fine tuning, and it required more memory before the price had come down.
Long release beta cycle for Win 7 and it became very popular and the standard
Then to Win 8 (You really need a start screen not a button...) The underpinnings go back to Vista though.
All in all, a gradual progression. Win 8 is a pig without the pretty pen, add Classic Start and now you can wallow back in the mud. Ah, heaven. Apps may be a plus, that remains to be seen.
