You're not being asked to pay anything to continue to use your hardware. Your computer functions just fine with 10.3.9....and every other piece of hardware you have works with it just fine. If you want the latest and greatest iPod, you have to have a somewhat new computer. If you don't have the latest computer (or at least one somewhat new), why should you have the latest iPod?
So my PowerBook I paid $3500 for just 2 years ago isn't considered "somewhat new" ?
All your arguments would work if this was 10.2, but this is 10.3, an OS that was the primary Mac OS, and had the main marketshare during 2005 and possibly a large part of 2006.