With the current payout system it makes sense to have a bot generating accounts which join all groups in order to collect a large fraction of the 20% payment which goes to the community. So for accounts to be able to earn from the community we might need to have a different incentive than just "existing". Also when moderators exist it makes sense that a fraction of the community earnings go to the moderators.
I think the key here is that the incentive is not to just exist, it is to deliver something which is voted up high by users. If bots are voting things up, that's money going to the real users too, so the bots just fizzle out.