Beat Every Dime Out Of It

Until it can make money no more, BEAT IT DO DEATH.

The over-saturation of a franchise could be caused by its creator(s) wanting to earn every single potential cent from its revenue, merchandise, and games' micro-transactions. This can only end with a Zombie Franchise situation being of the issue.

The Simpsons is a good example of its creator making a damn-good effort to Beat Every Dime Out Of It. It's been on the air ever since 1989 (if not for Season 1's "Simpsons Roasting On An Open Fire", The Simpsonsundefined would have been entirely in the 90s)