That's a pile a horse-shit and you know it. Dragonball was set up so it could have ended after any saga Akira Toriyama wanted it to.
Freeza, Cell, Buu, King Piccolo or Piccolo; it didn't matter which and only ended at Buu because he little go sick of doing it.
No one was holding a gun to his head or any ominous contract over him to make him continue. 'Save for keeping Vegeta, after the Freeza Saga, Toriyama wasn't known for giving a shit about fan outcry much less his editors when it came to Dragonball.