I demonstrated that you could still get a worse result with mutual cooperation than you could with mutual defection, which violates the T > R > P > S condition for the dilemma to be a prisoner's dilemma in the strong sense. I demonstrated that at least two of the four possibilities are unpredictable. Mutual cooperation doesn't necessarily give you a better result than mutual defection. Mutual cooperation could give you a much worse result than cooperating while the other player defects. For example, you could get a college degree like everyone else and end up working at McDonald's with $50k in debt through mutual cooperation. But you could also just work at McDonald's without getting a college degree (and the $50k in debt) while everyone else gets a college degree.

QED, sir.