Business is about staying in business, not being popular. A streaming pricing model, so you lose money on your best customers streaming 24x7 who get a great deal whilst keeping mediocre customers on a free tier because it is expensive. An advertising service where the audience is so tight they won't pay the price of a coffee for music streaming. Popular but sustainable? They already can't pay artists enough, only getting away with that because artists don't have a choice but to bend over.