What are you talking about? They asked McGregor and Kavanagh about Khabib a lot during the Maymac world tour where McGregor and Kavanagh both confirmed it.
Basic gist of it, McGregor said that he would like Khabib in Russia because "it would be like Rocky 4 or some shit", but "it's just one of many options". He wanted it because he's obsessed with the Forbes list, and Khabib in Russia + Maymac would put him at number 1 before the end of the year. But he also said that he recently found out that Forbes doesn't update their lists at the end of the year like he thought, so Khabib in Russia isn't as much of a urgency for him like it was before. But he still considers it the biggest fight PPV wise.
Khabib wants to pretend like he doesn't care about the Conor fight, because "I got money". But if he fights Fergusson first and beats him, Khabib vs Conor would be even bigger.