While it does suck for those of you that have to do it, you are paying for a software upgrade. I've never heard anyone complain that a new version iWork costs money. No one (rationally) complained that Leopard wasn't free.
It's only $20.
Except for the fact that AppleTv gets a (much needed) software upgrade for free. Ditto for the iPhone. It's not like the iPod touch is cheap, it's the same price as an iPhone at the high end.
If Apple was universal in charging for added features/software upgrades then I guess I could better understand the logic. Yes, it's only $20 - but $20 that I will spend elsewhere.