The main problem with this is how they compensate people who have already bought multiple character-items for the same account. Game time? 1-1 compensation in limited mogstation hard-discount? Is extra compensation as thank-you/sorry necessary? etc.
As a very large company, they need to be mindful of such politics.
Logistically, unless the change is "dire", it's unlikely they will push for prompt action to address these problems. They are very busy.
And finally, such changes especially having to do with real money, are 99% more sensitive than simply improving something in-game, for example. They have to ensure no exploits, bugs, etc.

So while it's straightforward for us, it probably haunts Yoshi-s nightmares in how he'll have to explain this change to the board.