Wasn't Taylor Swift born into a wealthy family? That's why she could take the time and chances to become a pop star. Not that I'm saying she isn't talented, she obviously is, but a lot of talented poor kids don't get that opportunity.

Direct to customer meaning they sell direct to a customer. Presumably through digital copies and owning a server rack.

You can certainly argue that even that kind of hypothetical billionaire shouldn't exist, and you'd be right.

Nah. Tons of merchandising, films, publishing etc.

Those Quidditch brooms and plastic wands don't assemble themselves in a sweatshop.

Think more like if some self hosted webnovel had the same success somehow, or if she'd been as involved with checking the conditions of the merchandise empire as thoroughly as she was apparently involved in making sure the child actors were treated well. Not particularly likely, but hypothetically.