I have thought pretty hard about your comment. While I don't disagree that many (perhaps better phrased as much stake) are extracting more than they add, I do disagree that Steem will benefit most from seeking to align users to it's particular goals.

"Participating does not in and of itself grow Steem."

The reason I reckon Steem should not seek to specify which users are most promoted is because I disagree with the quoted statement. Folks that troll, post pics of their breakfast or stolen memes are actual members of society, and their participation broadens the inclusivity of Steem social media - an existentially important feature of a social media platform intent on mass onboarding.

In fact all participation does grow Steem, although certain extractive participation also shrinks Steem more. Insofar as a particular viewpoint is promoted by design, this will be based on the particular biases of those doing the promoting. On Steem this will very likely be devs and cryptocurrency advocates, and particularly Steem boosters. This is a small subset of society, and such promotion will only seek that subculture, not the masses.

I find the idea of communities responsive to my expectation that the masses will sort per their values and interests. This potentiates the market for Steem to grow to the limit of the ability of communities to represent society, which maximizes the market for Steem best IMHO.

As you have pointed out, sometimes quantity creates quality, and this is true for financial markets and social media platforms alike.