Susan should have stayed where she was and where she was happy and functioning....people like Susan are not made for being the focus of such intense attention. fame is not for everyone. What worries me is who is looking after her finances....she's made a lot of money and when you have a lot of money you find yourself with a lot of friends and relatives...
Except she wasn't happy. When she first auditioned there really was no telling what would happen next. No other act on any of these shows has experienced that kind of overnight success. But once that had happened, there was little alternative. It would have been exceedingly callous to send her back to Blackburn (against her will) and end it all because of an apparent learning difficulty.
At some point she will stop releasing albums. There's no guarantee that they'll continue to sell in the 7 figures forever. But fortunately she wasn't a one album wonder and while sales for subsequent albums have fallen, they have still sold well enough and kept her busy. That may be particularly helpful in allowing her to transition to a less hectic lifestyle.
When her recording career does stop, she'll still be in an infinitely better position than if she'd spent the past few years unemployed living in her mothers old house in Blackburn in total misery. She'll always have options now.