Why is merging iCloud accounts too much to ask?

I have two iCloud accounts, that I actually use as the main iCloud account for my Apple devices and one that I use for Apple media and purchases. I come by these two accounts naturally: I acquired one back when I paid for a MobileMe account, and one that I created for my iTunes purchases (back when iTunes only sold music).

I am not alone in facing this situation. I know this because Apple devices explicitly support this situation, allowing you to specify a main iCloud account and a separate one for media and purchases.

But that’s a kludge. I don’t want two accounts, I want to merge them to create a single account to make my life simpler. You’d think Apple would want to support merging accounts as well, since they could then stop building kludgy support for two accounts. And yet years after people started facing this problem, Apple still doesn’t provide a way to merge accounts.

Why is a mechanism to merge accounts too much to ask? After so long I suspect there must be some legal reason. From both a user experience and engineering perspective supporting merging is the right thing to do. And when trying to understand why companies do things that don’t make sense, legal reasons is the answer more often than not.