Apparently there is a rule backstage, handed down from Vince McMahon himself to the creative team, that members of the reality show Total Divas are not allowed to win the Divas Championship. Up until recently it wasn’t spoken about publicly, but Brie Bella briefly mentioned it in an interview. Furthermore, there’s some frustration with how Vince McMahon wants RAW and Smackdown booked for the Divas. Some weeks he wants the wrestling shows to line up with the reality series, but other weeks it seems not to matter at all.
That being said, it’s said that the rule isn’t really set in stone, and nobody backstage would be shocked to see McMahon change his mind about it. There was talk about putting the title on Nikki Bella at Night of Champions, as the company spent a good amount of time building her up with Stephanie McMahon, Triple H and Jerry Springer all getting involved.
The first season of Total Divas debuted in July 2013, and since then the only two women to win the Divas Championship have been AJ Lee and Paige, who have traded the title back and forth.