I've owned a lot of iPods. My wife has owned a lot of iPods.
For the longest time, I could use gtkpod to seamlessly access my iPods from my Ubuntu desktop. It initially took some reverse-engineering effort to understand the iPod's data format to be able to access it from non-iTunes software, but it was possible. All of a sudden, Apple is trying everything they can to prohibit interopability.
First, they encrypted the firmware, blocking the use of third-party firmware like Rockbox and iPod Linux. This doesn't bother me much, as I always prefered the original Apple firmware anyway.
Then, in August 2007, they added a new hash to the database to block non-iTunes software. This was quicky reverse-engineered and support was added to gtkpod once again.
In November 2008, they changed the hash again. This time, Apple used code-obfuscation software on iTunes in an effort to complicate reverse-engineering a second time. When a wiki was put up to start documenting the new hash, Apple sent a takedown notice. Fortunately, some people found an ugly workaround to get gtkpod working again.
In 2009, Palm released the Palm Pre. It supported syncing with iTunes. Apple retaliated by updating iTunes specifically to block Palm Pre interopability. Unfortunately, this changed the iPod database structure, and the workaround for gtkpod no longer works.
While I can understand Apple not wanting the Palm Pre to be able to sync with iTunes, as iTunes integration is one of the main selling points for the iPod, I can't understand why they would actively block third party software from accessing the iPod.
Everyone is now selling DRM-free mp3 music, so it's not a question of protecting DRM. You'd think they would want to sell more iPods, not block a certain percentage of their market out.
My 5G iPod broke today. Dear Apple, the replacement I purchase won't be from you.