Bitcoin is generating revenue through transaction fees. I'm not saying this is the best way to do it, transaction fees suck. But Bitcoin and Steemit cannot be compared in this regard because their contributors are not compensated using the same economic model.

With Bitcoin, contributors are compensated by the users of the platform (through transaction fees) while with Steemit, contributors are ultimately compensated by the people who bought Steem money. The point is that the Bitcoin economic model relies on users (users leave, everything stops) while the Steemit economic model relies on people buying Steem money (users stay but these people leave, everything stops).

As long as you'll have more people wanting to cash out than to cash in, the fact that Steemit is a token system is irrelevant. For now, contributors will want to cash out. So again, the question is how do you create a revenue model that allows Steemit to be sustainable during the period needed for Steem money to become value in and by itself (thus making cashing out irrelevant).