This statement is either so broad that it is obviously false, or has so many implied additional conditions that its application is incredibly narrow.
* The time horizon used to judge incentives vary person to person.
* Willing martyrs exist for various causes. Therefore, it is not just the incentives that matter, but the belief about those incentives.
* Self-sacrifice for others exists (e.g. a mother rushing into a burning building for the chance of saving her children). Therefore, it is not just the incentives that matter, but also the subjective weighting of conflicting incentives.
* A person may spend a great deal of time researching betting patterns for playing craps, none of which can overcome the house's advantage. Therefore, it is not just the incentives that matter, but the knowledge of the outcomes.
* Somebody may work in an oppressive environment for their entire life, rather than changing careers. Therefore, it is not just the effort required that matters, but also the relative amount of effort on different time horizons.
While I agree that incentives are the best way to move population-level behavior, and is usually a good starting point for understanding individual behavior, your categorical statement doesn't have those caveats.