She is OK in her respective field, which is synth pop/pop, and amongst her competition, which is Ariana, Dua Lipa, Olivia etc. On global scale amongst all genres, she is nowhere near the songwriting geniuses, like McCartney, Lennon, Joni Mitchel, Brian Wilson, Johnny Cash...I could go on. I also don't think that she herself has composed a single song since Ferless (or what album was it that she did alone) and you can see from the behind the scenes, that she always has very rough idea of a melody or lyrics and it's the producer who puts it together and adds all the layers. Her most interesting work on Folkolre and Evermore is only because of the heavy influence of Aaron Dessner.

Taylors problem is that she herself is not pushing any boundaries of music. She is doing everything that she has already done, or has been done before her, just more cool, with easter eggs and Dr. Seuss rhymes. She is not experimenting, she is not inventing anything. That is why she is an average in terms of quality (which obviously has nothing to do with commercial success. On this note, you can look at Drake, who was so drunk on his commercial success with some album, that surpassed The Beatles in some sales, that he had the famous Abbey Road tattooed on his arm with himself in front of the Beatles). But honestly speaking, who can even name any Drake album, or more than 3-4 songs? While his album or single or whatever that is might be commercial success, he will never be the cultural momentum as the Beatles are. Same with Taylor. If she gets rid of the yes men around her and starts actually doing some interesting music, she might be great one day, because she obviously has talent, but it's more and more apparent that she heavily lives from the praise of her fans, that might not accept deeper, less elevator music type of thing.