It's your sense of social obligation that's been triggered - these folks have shown faith and commitment, and expressed it concretely and irrevocably, and that's what you're responding to. It's not the money - as you've said, that's small in absolute terms. As usual, cash is a hygiene factor - you needed some to get you committed, but more won't make any difference - it won't make you write faster or more often (unless it's enough for the step change of giving up your day job).
It's your sense of social obligation that's been triggered - these folks have shown faith and commitment, and expressed it concretely and irrevocably, and that's what you're responding to. It's not the money - as you've said, that's small in absolute terms. As usual, cash is a hygiene factor - you needed some to get you committed, but more won't make any difference - it won't make you write faster or more often (unless it's enough for the step change of giving up your day job).