This is the most simlpe way for you to understand it.

Khan-Pac would be a MEGA fight earning EVERYONE involved TONS of lovely lolly. Fact.

Had Khan been beaten on his journey towards potential mega-fights he wouldn't even be considered now for Pac-type fights. That's why you don't take risks overmatching a money-making machine. Fact.

Also.. I believe Khan only has one fight left with his current Warren connection