*Membership spots not really limited!
It's possible. I mean, if the WWE swerved us and played the Rock/Cena thing for another month, Cena can win the title at Extreme Rules. He comes out on RAW the following night and is attacked by Brock Lesnar who demands a title shot. Cena is ready to accept but COO Triple H refuses to grant Lesnar a title shot because of his lose at Wrestlemania, saying that Lesnar hasn't earned it. The next month is filled with Lesnar attacking Cena during his matches, while Cena is booked to fight somebody like Chris Jericho at Payback and Lesnar gets put into some type of number one contender match. At Money in the Bank, Lesnar finally gets his match with Cena and wins the WWE Championship. He comes out on RAW the following night and claims that he has beaten and broken everybody the WWE has put in his way and that there is no longer anybody in the WWE that is any type of threat to him. Cue "Cult of Personality," the fans go crazy and the Best in the World returns to extract his revenge and get a title shot at Summerslam.
Damn, I just planned the WWE's main event for the next few months. Where's my paycheck?
None of that will/could happen because Lesnar is on a certain number of dates and it would burn through too many of them too quickly.