it's the same as on steemit, surely steem has some possible improvements, which can be made in the future..
I think after x amount of time, in this case a week there needs to be a final point where the earnings are taken or something.
But i might be shortsighted in this, but i don't see why this can't be reset every week (ofcourse people that already upvoted can't do it again, or at least not influence it again.)