If you had asked me to make a wager on whether or not a taco made with a Doritos shell would be a wildly successful fast food item people would want to consume, I would have bet against it and lost.
Damon Krukowski, a musician for the bands Galaxie 500 and Damon & Naomi wrote up a nice piece for Pitchfork about how music streaming services like Pandora and Spotify aren't very good business models for musicians who license their music to these services because they don't pay well—even if their songs are played millions of times.
I was also impressed by Swift's ability to market herself well. She really is a marketing genius. When her newest album came out, I bought it, not because I had been waiting to buy it, truthfully, but because buying it was the only way you could listen to it.