It's performing so poorly because it has had an inflation rate north of 10% through much of its existence. You are comparing it to coins with low single digit inflation rates. Of course it is going to perform worse. The reason steem has performed poorly is likely due to a whole host of reasons, but if you need your users to act altruistically for your platform to succeed, you platform is not going to succeed. It needs to be designed in a way for people to act like normal people and it not cannibalize itself. The current incarnation is not that.