I do not think Swift has a good voice compared to others like Adele and Aguilera. A LOT of pop females sound the same, or they sound like they are copying Alanis Morisette.
It is interesting to research and see those who use Auto Tune and those who do not.
https://en.wikipedia.org/wiki/Auto-Tune
Taylor Swift is a brand. She’s popular, because she’s smart. She’s built an empire for herself.
Adele and Christina are genuine singers. Aguilera’s vocal range blows my mind.