I'm sorry but I don't believe that. I do understand that line of thought if you are in a very complicated personal/financial situation but you're stating that the only driver is money, which is clearly wrong...

Altruism is not a default position, and is unusual in the real world.

I'm not saying that's how it should be, or that people shouldn't work to make it otherwise. But you say why don't all those people walk away from that? How far would you go? What if you had children depending on you? It's very easy to condemn other people as "greedy" but you show a lack of understanding, of empathy, perhaps, for how people in general function in the world if you assume they should just do what you say because "obviously, my moral stance trumps their concerns."