I think Dana will never do cross promotion fights. UFC has been in business for tens years, and Dana only allowed Chuck Liddell to fight in Pride once (other promotion), Conor McGregor to have a boxing fight against Mayweather (boxer), James Toney (boxer) to fight against Randy Couture under mma rules and wrestler (the one that is a fake theatre) CM Punk fought 2 times unsuccessfully in UFC. That is it. Only 5 unusual behaviour or allowance from Dana during whole UFC life.
he must have given them the chance because he is also gaining those matches. i have yet not noticed UFC politics during those days but i think Dana was more confident in the fighters that he allowed to do cross.
but obviously, Dana also has favoritism among the fighters that he wants to make it to the top. the ones who kisses his aass often get multiple title shots in the same weight class while not fighting to earn his next title shot.