There is no Apple TV developer agreement other than those very specific ones (eg Netflix, Hulu, etc). Apps running on iPad wouldn't automatically be supported by a 4th gen Apple TV. The developers for the MSO would have to do that.
And if Apple tries to support it themselves, MSO simply pull the apps from the App Store.
Apple has no real choice but to negotiate with MSOs if they want to deploy a 4th gen Apple TV with apps, games AND cable TV.