Yes, ideally you have both. You have a system like Steem that allocates money to good content and contributions and then you have sponsored posts as the world is still commercial and companies wants to advertise and good targeted advertising is not that bad.

Remember how Digg had that model where advertising was voted, just like content and good ads had to pay less to advertise than the shitty ones. I think this could totally come back to Steemit and when doing so, those ad revenues would add to the platform value and be good for all of us.