final fantasy got big off of one game whereas zelda kept improving in quality and garnering an audience for being an amazing action adventure dungeon crawler.
The main thing FF7 did really was introduce the mainstream to JRPGs... Zelda completely changed the industry
Let's be honest 90% of GAF probably didn't know what Final Fantasy was until FFVII started appearing on the Playstation magazines
I know this post comes off as bait but really.. FF is regarded for FF7. Not FF6, not FF5, not FF9, and especially not 10 which is divisive in its own right
Zelda's known for more than just Ocarina of time, Zelda's loved for ALTTP, Wind Waker, Twilight Princess, BOTW, and my beloved Majora's Mask.
90% of the time a FF fan's favorite FF game will be FF7. It's not so certain for Zelda.