I partially agree with you, but you are forgetting that even if those people leave Steemit once the lure wares off, they have to do it by powering down. Even if they never invest, registering the account entails STEEM they can't touch immediately in whole, and if I understand it correctly even in part, for two years. I am talking specifically the "free money" in each account. Once would assume that this would keep STEEM more stable than even Bitcoin because of this. Even when STEEM rises due to traders trading it, most would do their due diligence and many would end up singing up for Steemit themselves. Even when WHales power down, they would always have more in than they are able to take out.