You have more choices available than either climbing the corporate ladder or sitting on the couch watching Netflix. Neither of those lead to any sort of fulfillment in my opinion, so I don't know why you would limit yourself to those options.
Also the idea that if you don't win the competition and reach the top of the corporate ladder you're doomed to a life of failure and misery is just pure nonsense. By definition, the vast majority of people will not reach the top.
Life is not a constrained game like the Prisoner's Dilemma, you aren't limited to "lie" or "confess", you can also tunnel out with a spoon, bribe the guard, find a loophole in the law, etc, etc. You're only limited by your imagination.
> billionaires can optimize for the sake of optimizing, rather than to keep their head above water
No, I would imagine billionaires optimize for the sake of being better able to do whatever made them billionaires in the first place, not just for its own sake.