People forget how big DC vs Jones 1 was. Both were undefeated, neither had lost a round in their career except Jones vs Gus, both from super camps, both were high level well rounded fighters...and then the fight that happened at the press conference and then the hot mic argument...that was a really big fight.
Others that people mentioned that were close to or just as big as Khabib vs Conor were:
-Chuck vs Rampage
-Chuck vs Couture 3
-Rampage vs Evans (had a LOT of hype and rivalry)
-Evans vs Jones (had a big build up and lots of drama as well because of the Jackson/Wink situation)
-GSP vs Hughes 2
-Brock vs Couture
Some of these may have even felt bigger than Conor Khabib because casuals knew both fighters, while most casuals have no idea who Khabib is, and because some of these fighters were coming off impressive winning streaks or were undefeated, and Conor just got finished in a boxing match and got finished in an mma fight the year prior to that.
By the way, I watched UFC 1 live on ppv when I was like 11 years old lol. I saw a commercial for it and convinced my parents to let me order it.