Quite a thoughtful comment.
I do agree that sneaky ninja selfvotes and botvotes at the last minute prepayout are a result of the 7 day payout period, which also renders posts with longterm benefit devoid of purpose. Who would publish 'Moby Dick' on Steemit? It's a strong disincentive to produce lasting content, which is counterproductive of Steemit's highest potential to benefit society.
Also, there are ways to incentivize upvoting others rather than yourself. Code is infinitely mutable, and while penalties for selfvotes are easily sidestepped, incentives to upvote others instead encourage behaviour that benefits the community, rather than trying to prevent behaviour that doesn't.
Consider the impact of increasing curation rewards for each successive account upvoted in a given day, week, month, etc. Coupled with strongly limiting bots, such an incentive could radically impact curation, and thus rewards for content creators.
Thanks!