Is it wrong to be selfish and not think about the greater good of the team/project/company? Primary, or highest ranking, responsibility for this is the company

Is it wrong to be selfish and not think about the greater good of the team/project/company? Primary, or highest ranking, responsibility for this is the company's (and so management's), not yours. If they are significantly underpaying you, that's a risk that they chose to take on. If no people will die, planes fall out of the sky, etc., I'd say that, speaking generally, one should be able to leave with a fairly clean conscience, barring any obligations of more personal connections (true, mutual connections -- not e.g. propaganda about "our marvelous environment"). That said, I know nothing about your personal circumstances. So, it remains your call.