Way-way-way back when, I was an Opcode/Studiovision user. Then Gibson bought Opcode in 1998, and I immediately switched to eMagic. Then Apple bought eMagic in 2002, and I bought Logic. Somewhere along the line, you needed an Apple ID to purchase Apps, but I do know that I did have a purchase registered in 2013. Being one of those people with more than one Apple ID, my "purchasing" ID was tied in with my business account, but having retired I am losing my business emails, ID, etc. so yet again I had to purchase Logic Pro X using my (now one and only) personal Apple ID.

I guess I can sorta understand, but it is annoying to have to repurchase software because of Apple's unwillingness to allow merging of Apple IDs. At least it doesn't cost an arm and a leg like it did back then (for example, you had to pay extra for things like the ES2 softsynth, etc., people would spend literally thousands for everything that is now included), and at least it's not a subscription (shhhh!!!).

If you still have access to the "business" Apple ID you might be able to change the email address to a personal one. https://support.apple.com/en-us/109353

The solution Apple offered me was to make my professional ID part of my "Family" and share applications, but for tax reasons (as well as to simplify purchasing and subscriptions in the future) I opted to delete my professional ID. I will also lose some media- books, music, etc., but that cost is relatively trivial. Logic Pro X was the one big expense. Cost of not doing business, I guess?