Georges St. Pierre was one of the highest paid fighters in UFC history, thanks in large part to getting a chunk of the Pay-per-View revenue for each of the fights he headlined. He's rumoured to have picked up a $5 million payday from a single fight, almost unheard of in the UFC (Brock Lesnar, Ronda Rousey, and Conor McGregor are generally thought to be the only names to generate that much income from a single UFC fight). He also has a budding career in movies, with appearances in Marvel's Captain America: The Winter Soldier and the upcoming remake of Kickboxer. With no financial need, there's one less motivating factor for GSP to come back. Plenty of fighters squander their fortunes, but GSP doesn't seem to be one of those, either.