Glory
"I'd like to thank The Academy, mom and dad, my girlfriend, my money laundering friends in Russia…." The glory can come with a successful (or at least critically-praised) film. Especially during awards season. Most of a producer's glory, however, will only be recognized by others within the industry.
This recognition is good enough for many. The more successful a producer is, the more talented (and wealthy) people want to be involved with them. The more these people want to work with a producer, the more successful they can be. If you can get a few successes, it's a model that sustains itself indefinitely—or at least until you make Battleship and people stop returning your calls. ("Kablooey…you sunk my career").