a new idea just occurred to me while reading here (not mature at any rate):
can we separate the roles of investors/authors/curators?
that is, each account can only be set to one role at a time (but you can change it after a given period), pretty much like choosing professions in games. So we can have specialized investors, authors and curators earning (additional) interests, posting rewards, curating rewards respectively but not at the same time. Then one can focus on only one activity at a time but is free to choose differently in the long run. Steem price will be every class' concern. A curator can still post, but the posting reward will not realize and an author can still vote, but no curating reward (but an author's vote with no financial incentive behind it might carry some good information re the content though).