"You get an idea" doesn't mean you know for certain
His most recent fight, meaning the most accurate number we would have, was not even reported (Khabib) because 205 didn't release salary.
Actualy I don't think Ferguson's last salary was released either.
So yeah, you literally DONT know how much they made.
And more than that, the more important point here - and that's value. The UFC perceives Khabib to be the more valuable fighter. So they will pay him more. They don't think Ferguson is on that level, so they wont. What, you think they can't sell Khabib Conor if the Ferguson/Khabib fight doesn't happen? Or maybe you think they can go into Russia and sell a card with Tony Ferguson as the headliner.
Blame Ferguson, he set the world on fire with a win over RDA in a mainevent and had the chance to steal some headlines and play the game. He didn't. Sucks to be him. You're just pissy because a fight you want to see wont be made, this kind of shit probably happens all the time. The mistake Dana made here was making it public.