Never thought I'd vote for TD for something, but as far as impact, culturally and all that it is TD without a doubt.
1989 was massively successful but nothing stands out about it in regards to the hit pop albums of the world. It was safe (looking and sounding), the visuals were great but not unique, and the hits fit snugly into radio without having a distinct stylistic point of view. Basically you could have swapped any other popstar into Taylor's place and it could work. TD was much more impactful from concept to execution, the songs that were hits (most) were more impactful, and its unique to Katy.
Teenage Dream, 1989 singles are already forgotten, plus it was inspired by TD
both Shake it Off and Wildest Dreams had amazing longevity better than any song from Teeange Dream (Firework being played every Fourth of July doesn't count as longevity )
also 1989 is #3 in the US a year and a half after it came out