Pride wasn't all about co-promoting, but wasnt against it as much as the UFC is these days with their exclusive contracts.
I'm sure there was a bunch of money that was handed over to Pride to let the UFC posterboy (chuck at the time) enter their grand prix. It wouldve looked real bad if chuck won it all.
What I dont get was back then, when Pride was the big show, dana was hootin and hollerin about Japanese promotions that did not want co-promote events. Now that the UFC is the big dog, he doesnt allow any non-contracted fighters in his shows all with no exceptions.