Khabib's right what he says they need to pay him. Even Conor said Eddie alvarez was stupid for accepting the fight on his original contract, he should of renegotiated it to fight Conor and they all know it.
I don't particularly agree with your last point though. Khabib is the rightful champion. He pulled out of a few fights but he turned up for the championship one, it was Ferguson's injury and then a load of feck ups that meant he had to fight Iaquinta, he turned up to the fight and fairly won a title. You could also counter it by saying McGregor never fought at LW and was gifted a title shot because of who he is, I don't have a problem with that happening but I would also say it's fair to say Khabib is the champion and there should be no question about that.