[TheOtherHobbes]

You need a certain kind of personality to be responsible financially, and it doesn't overlap with the personality required of a pop star or sports star.

Quite a few stars get scammed. "Our accountant/manager stole all the money" is not an uncommon thing.

Music and sports both have shady links to organised crime, so it's not a given that stars are going to be surrounded with the kindest and most professional people.