> I’m suggesting a path forward

IMO you are not suggesting a path forward as much as suggesting what has been done over and over again for the past two years (with little, if anything, in the way of real progress).

> The recent call-out of @ranchorelaxo is an example of what I mean. It’s telling that he/she/it did not defend themself (yet) but instead @haejin did.

And then what? No response at all, and as far as I can tell @haejin is still earning something like 6000 USD per day (i.e. 2 million USD per year) for doing little to nothing to add value to STEEM. It isn't a small number either, that's around 0.25% of the entire market cap of STEEM going to one person/scheme with little or nothing to show for it. Even if this individual 'calling out' approach were effective, what would happen is that the account would quietly go away and the scheme would be rehatched under different names, possibly different 'content', etc. The one thing that remains the same is the clear incentive to maximize individual earnings. 

After two years of repeated and unchecked abuses (despite numerous calling outs), it becomes very much a question of the insanity of doing the same thing and expecting a different result. 

> long-term rational self-interest

Long-term rational self-interest at the moment probably coincides with just maximizing individual earnings, because so many other people are doing it anyway and will very likely continue doing it, especially when the best answers we can come up with are: a) more of the same; and b) some poorly-defined and poorly-analyzed future 'solution' that probably won't ever even be fully implemented before moving on to something else (which is actually more of the same: Remember when 'curation guilds' were the solution, and then linear rewards?). 

> irrational short-term decisions which harm others and oneself in the long-term.

It is tempting to equate decisions which benefit oneself at the expense of others as irrational, but that is wishful thinking and moralizing, _unless the rules of the system make this irrational_, and they currently do not. Nor is it clear that @haejin earning around 2M USD/year is in any way irrational (for him and his affiliates).

> I’m also not sure what technical or system solutions would improve this activity since it’s a common thing we see in most systems with humans involved.

The most likely solutions I see that would probably work are:

1. Dramatically increasing curation rewards so that most of the reward pool is paid out as a combination of effort _and staking_ which takes away the free ride. If you want to earn you have to invest money, which at a minimum gives a lot back in terms of raising the STEEM price. (Alternately there could be a system where content rewards are similarly scaled by STEEM/SP staking but no one has proposed anything well-defined.)
2. Moving away from the socialized reward pool, which has been an interesting but unfortunately failed experiment, and toward low-friction tipping. When presented with the opportunity to spend (and especially with the opportunity to receive) money paid for by 'others', all or nearly all of the human systems you describe (and most certainly this one) devolve into waste and corruption. What fixes that is people spending their own money.
3. Reduce barriers to downvoting including: a) Remove annoying and misguided popup in UI; b) restore symmetric UI (upvote/downvote vs. 'flag'); c) separate pool of vote power for downvoting, so downvoting does not become a direct opportunity cost to the voter (as it is currently); d) research some cryptographic method of anonymous downvoting to prevent retaliation; e) Statements by founders/developers/leaders on the platform on the importance of a downvoting when needed to maintain the integrity of the system and restrain otherwise-misaligned individual incentives (at least mirroring what was in the white paper, and in contrast to a lot of the nonsense that has been previously stated by many of these people about only using downvotes for plagiarism, etc.).