This is a massive problem that can kill any community. We see it all the time in the open source communities, and there is a distinct need to find ways to limit the application. The fact that Steem posts are tied to "currency", and the mechanisms around it tend to encourage quality to a certain degree, means that we have some things to work with.
However, as you note, there is still the issue of "gaming the system", which we are also already seeing in play. Its a tricky balance. I'm hopeful that the interlocking series of valuations (posts, replies, upvotes, steem, power, dollars) can provide a bit of a hedge against this.
I'm looking forward to the next post an more of your thoughts on the topic!
RE: Steemit: Defeating the Tragedy of the Commons