To be perfectly honest, if you give this whole fight thing enough time, there is a chance that Islam can rack up enough wins and be in contention to make a shot at the title.
If Islam by any chance wins that title, and starts defending it (even once), it will actually (implicitly) lead to Khabib himself being blocked from fighting in the UFC as a whole.
- No way Khabib faces Islam for 155. They're allies.
- He and Usman are fellow muslims and allies so he can't fight him either.
- Khabib has his undefeated record to preserve so he'll more or less be kept away from 170 (unless he really wants to move up but I doubt it).
- He's not getting any younger and father time always wins, so younger hungrier guys are going to give older guys tougher fights anyways.
To be honest, UFC and the staff there should just leave him alone. He was a big draw mainly because of Conor and won't be as big of a hit if Conor isn't in the limelight.