A service pack doesn't completely redesign how people interact with Windows, though. But OS X "service packs" tend to do just that. In fact, that was the author's frustration.
Seeing as OS X service packs also come out very frequently, whereas Windows are very rare, I'm not sure the two are comparable.
I should probably bow out now. I just thought it was interesting.
I think the principle attribute that determines how long support lasts is the cost to get to the next supported version and not anything to do with feature differences. Apple made the decision to give away upgrades precisely so they could move people off old versions I suspect.
> Support for Windows 7 RTM without service packs ended on April 9, 2013.