To be honest, like most other crypto coins and assets, if the system does not yield any inflow of cash other than newcomers can be a ponzi scheme. money has to paid somewhere and steem like other ponzi milks on newcomers and it requires newcomers to stay afloat. I don't know why people thinks voting=$ is a good idea. it makes totally zero economical sense. so the problem is not the bots, not the self voting, but rather its the system that's flaw.