For some reason they're not mentioned in the same vicinity, but when you look at it objectively they should be closely ranked/rated.
Khabib: 13-0, 4-0 title fights, 8 years
Total UFC record of Khabib's opponents when facing him: 89-33-1 (2) [71.2% win rate] . Total UFC record of opponents after facing Khabib: 37-40 (1) [47.44% win rate]
Usman: 14-0, 5-0 title fights, 6 years
Total UFC record of Usman's opponents when facing him: 110-31-2 [76.92% win rate] . Total UFC record of opponents after facing Usman: 28-21 (1) [56% win rate]
In fact, there's a solid case Usman should be ranked ahead of him. Usman:
- actually beat the champ (x4 defending) to become the champ, whereas Khabib beat #11 Iaquinta.
- is the more active fighter and champion. Khabib had 2 interim champs in his reign.
- has faced a wider range of skillsets, including bad matchups.
- didn't retire in his prime and is doing rematches.
- has never missed weight or been suspended.
Some say Khabib beat 3 top P4P fighters in a row, but this is disingenuous. Justin and Conor's P4P rankings were extremely inflated. Usman may not be as dominant as him, but he's dominant enough in his own right.
You can bring up Usman's submission loss to Caceres...
...but this happened around the same time as this fight, a fight Khabib realistically should have lost.
All in all, they're both generational talents, but I'm tired of seeing them rated differently as if they're not in the same league. As Usman continues to merk people I think this narrative will become more popular.