I honestly believe Apple is offering these fairly minor and necessary updates to iTunes simply because they have to. It's been a long while now since any update offered anything beyond cosmetic changes, support for new devices and marketing tools such as Genius and Ping.
The basic functionality of iTunes has changed little for several years now and has had new features merely bolted on top of what was already there.
I would be surprised if the next major update to Mac OS didn't include a major iTunes update of some kind. It's about time that Apple went back to the drawing board and decided on a new roadmap for the iTunes product. Personally, I couldn't care less whether it's 32 bit, 64 bit, Cocoa or Carbon - I just want the features of the programme offered to me in the best way possible.
Apple have some decisions to make about what they want iTunes to be. Is it a Media Player? An online store? A social-networking tool? An iPod/iPhone/iPad syncing utility or all of the above? If it's any or all of those, then Apple need to decide how best to present it, because the organic growth culminating in iTunes 10 hasn't been great and is surely unsustainable in the long term.
So I believe there's a team of designers and engineers at Apple just waiting to begin work on the next major overhaul of Mac OS and its major constituents, such as iTunes.