Reason #1: The last time 2 Chainz was signed to another rapper's label, it didn't work out so well.
As a member of Playaz Circle, 2 Chainz (then known as Tity Boi) and his partner Dolla Boy released two albums, Supply & Demand (2007) and Flight 360: The Takeoff (2009), on Ludacris' label Disturbing tha Peace. And while both spawned minor regional hits, neither really gave 2 Chainz or Dolla Boy the kind of visibility you'd expect. Part of that was because they never got the right push from the label. But, a larger part of it was because they were simply stuck in the mix with a bunch of other artists signed to Luda. That tends to happen when you're signed to a major rapper's label. And, who really wants to be put in that situation?