You take less money up front with the hopes you eventually make more later on. All wrestlers signing to NXT do it. LA Knight said that’s the reason he took longer to get to WWE, because he wanted to be able to financially handle the initial pay decrease from what he was making in TNA. But once you’re in main or at least have spent decent time in NXT, then your pay goes back up and you make way more then, especially with merch sales and licensing deals, etc.