Its like a ponzi scheme with the difference, steem makes sure you cant withdraw your money for 2 years effectively, so its like a pyramid that you cant take your money out of. Initial users/investors have the most benefit, in the long term new users(if they come) wont make much money at all and will leave or not be active. Its an interesting concept and a different take on the pyramid scheme, one with rules that make the pyramid bigger. Everyone in on it already stands to gain i believe

invest only as much as you can afford to lose

This one might just be worth the risk as for early investors the reward is far greater than the risk