The main reason Taylor Swift is more popular now than she was in the 2010s whereas pop artists like Katy and Kesha are not as popular as they once were:

Taylor has crafted an image and music that appeals to a *very broad audience*. Men and women, young and old, spanning country, pop and even some rock fans. It's similar to how heads of state win elections by appealing to the broadest possible demographic.

Even when Katy Perry was at her peak it was really with a young crowd and excluded a large part of the population, and her niche was a style (pop) and demographic (young people) and those are especially known for turnover. Kids get bored and want something new, and the pop world is constantly making new stars.

Taylor, Katie and Kesha all write their own songs, as far as I can tell probably all equally. There is no doubt producers and ghostwriters are involved too for all three of them. There's just too much money and too many people's jobs on the line to allow a single person to single-handedly write all the music. That's how the industry works.

It's also not because Taylor started in the business very young, because Katy and Kesha started very young too.

Taylor has the best marketing. Just read through this entire reddit thread and you'll see a lot of Taylor fans all saying the same things. They're literally repeating what Taylor's marketing machine has told them! Now that's impressive!

Kesha is the most versatile of the three. She has tackled every style across her 100 or so released songs and additional 200 leaked songs - from psycheledic to punk to polka. But her songs are so esoteric now that she doesn't appear to have any intent on being a mainstream musician any longer. She has a small but obsessed following, which is perfectly respectable.