I think changes need to be made at the blockchain level to address these issues. And I think Steemit Inc. IS addressing these issues, though indirectly.

When SMTs are implemented, there will eventually (hopefully) be a bunch of new sites using Steem. Some of these will eventually figure out better ways to deal with the conflict of interest between good curation and pure profit seeking.

They might implement, for example, a system where you can’t constantly upvote the same authors. Or allow for multiple payout periods, so that good content that happens to be more than a week old can be discovered and upvoted for years instead of a week. Or something else that nobody has thought of yet.

And maybe Steemit will learn what works better from these new sites and implement those same features as well.