Sponsorship is probably the biggest issue, but I don't really know enough about it to comment. However, my point was that he could possibly/potentially make more from a UFC contract (all things considered) than he would by staying with WSOF. I'm not sure if they have the capacity to pay him more than they already are whereas UFC could if he rose through the ranks. Not saying it would happen, but it could. That said, it would be a toss-up and like you said, his immediate paycut would come with higher competition.