Those stories made me laugh.
The billions people spent on her wasn't all new spending. It was mostly spending that was being drawn from forms of entertainment that people would have spent on instead -- a substitution effect. People can't measure the unseen dollars that would have been spent elsewhere if Taylor Swift hadn't come to town to do a concert, and you got a lot of misguided stories falsely giving the impression that she was adding money to the economy. Yes, her fans were spending a lot of money. But spending money is not the same as adding money to the economy. You need to not only look at what you can see (her fans spending money), you need to also be able to account for the unseen (that limited money her fans have not getting spent elsewhere because they decided to see her concert instead) to understand the true economic effect. Bastiat, a French guy from the 1800s, explored this, writing about "that which is seen and that which is not seen."