I never said he shouldn't be able to make credits. But he asked for the incentive and I think the incentive for exploring should be finding new, uncharterd worlds. I like bounty hunting and my incentive to kill pirates is that I like lasers and explosions. That doesn't mean that there shouldn't be higher payouts for your activities on planets, it's just an answer to his question.
I agree that, initially, the incentive should be to do something you like, otherwise, you might start to hate the game if you do things only for credits. Sorry if I misunderstood your point. But exploration has been the poor child of ED activities for a long time now.