Neither Teenage Dream nor The Fame Monster are iconic albums. But TFM unquestionably had a bigger impact on pop culture. "Bad Romance" was everywhere and the hype for "Telephone" was insane. Nothing in the Teenage Dream era could even compete with that.
Teenage Dream had a lot of hits, but The Fame Monster was a mega-superstar at her absolute peak of pop culture dominance.
"California Gurls", "Teenage Dream", "E.T.", "Last Friday Night", "The One That Didn't Go to #1 Despite Multiple Remixes and Discounts", "Part of Me", and "Wide Awake" are all forgotten. That's 87.5% of the era. How tragic.