I suppose that the frontpage space might be an issue for payouts or income distribution. This might limit the rewards to go mostly to the "hit" posts. But if there are future iterations on this concept of income based social networks where participating actualizes tangible value (in dollars) for the participants, it seems a better solution than ad revenue that only goes to a given platform operator. Also, Steemit may administrate other reward incentives for Steamians in the future that we may not know about yet.