Depends on the definition of "make it". If that means make good money, yes, his celebrity could get him some nice paydays. Boxing fans would tune in to see the MMA guy get starched and MMA fans would tune in hoping to say "see how good we are, and we can kick, knee, elbow, wrestle and use BJJ". The money is there.

But he absolutely could not be a top guy. There is a huge gap between good MMA hands and good boxing hands. A chasm.