We already know the answer. Her oldest songs are already 20 years old and still incredibly popular and recognizable, namely Love Story and You Belong With Me.
ABBA broke through in 1974 after winning Eurovision. Gimme Gimme Gimme came out and that video is from ~1979. They broke up in 1982. ABBA had a resurgence and attained their current popularity in 1992 when ABBA Gold, their Greatest Hits album came out. That success then lead Benny and Bjorn to write the Mamma Mia musical which debuted in 1999/2001.
Taylor released her first Billboard charting album in 2006. And released her first album to win Album of the Year, with songs peaking at 2 on the Billboard 100, in 2008. Even if she stopped making music there, in terms of time you could say her rerecording of Fearless in 2021 and the Eras Tour would be comparable to her โABBA Goldโ moment, coming 13 years later.
So Taylor has already โstood the test of timeโ and remained popular for longer than ABBA existed as a group, and as long as the time period between when they broke up and when ABBA Gold came out.
If someone doesnโt think she has stood the test of time, itโs probably because theyโre so old they think 2008 was yesterday instead of nearly 20 years ago. Or so young they think Taylor Swift became popular 3 years ago.
Iโm not a Taylor Swift hater, but when you hear these classic songs you question whether or not her discography will stand the test of time. Sheโs very commercially successful and has broken records. But I donโt think her music will have the same cultural impact as legends like ABBA, Michael Jackson and others who we still listen to 50 years later.