Good point made by Utah though... A lot of windows users couldn't care less about using windows 98 even though there is ME, 2000, XP after it. I would probably take that as ignorance, as usually either 1) have slow computers so 98 is the best choice or 2) they don't know anything about the updates, and when they encounter them on other computers, say thats nice and just go home.
The rather small macintosh market has lead to its users knowing a hell of a lot more about their computers than the average windows user. It's my believe that is why we upgrade whenever one comes available (although, there are excepts, like the win 98 people, need to use previous versions, say OS 9).
On top of this, Apple has made it difficult for OS X users, because they force people to upgrade by offing their software only to the new 10.x revision. Usually the upgrades are worth it, and always throw more features than Microsoft has ever included in an upgrade (note 98-ME!)
So yes, it was a fair point. I upgrade everytime one comes out, but I like being a BETA tester

Like someone else said, a lot of professional Mac Users wait until all their software is supported in the Upgrade.