Every year or so I like to check which of my four known Apple IDs has my many Apple hardware purchases associated with it. Two years ago, for example, they all jumped from one Apple ID to another. I assume Apple has a very broken distributed database system, and they try to associate records based on metadata like phone number, mailing address, email addresses, etc. Move a key around, or change the matching algorithm and purchases hop.
Today I’m pleased to report that they’ve now settled into two accounts. For a while they were all with the Apple ID I use for iTunes purchases (but not for iCloud — due to technical bugs/issues with Apple’s id infrastructure). Before that they were with an old dev account. Today 3 purchases are associated with my iTunes Apple ID, zero with my iCloud Apple ID, and 17 with the old Dev account. There’s no obvious logic for which purchase has gotten which Apple ID. Note that the old dev account is never used for anything; it’s completely inactive.
I guess I better tighten up password security on the dev account. I’ll try associated a phone number with it, that ought to really mess Apple up.
If you want to know when Apple lapsed into incompetence, just track their identity management issues. (Hint: well before Cook took over.)