Thanks for you substantive response, that provided me information I didn't have before. No one has mentioned, nor have I read, that downvoting costs voting power, until you (I am just about to tackle the white paper, if I can stop myself from commenting).
I have noted that a whale not self voting would be essentially throwing away $100's or $1000's weekly, and that this is a strong motivation for them to NOT vote on the posts of others. Recently @jerrybanfield posted that, instead of selfvoting for an estimated $1800/week, he was going to upvote others posts. This made quite a stir.
The fact that it made quite a stir shows that it's not a common practice.
I still do not understand how krill like myself having a downvote might have any affect on the reward pool. The fact that 1% of accounts receive 99% of author rewards (at least up to HF19) shows that whales upvote their posts and do get almost all the new Steem thereby.
Downvotes seem to have nothing to do with it.
Your (colorful) explanation of how downvotes discourage content you find objectionable is more understandable than how I have viewed that discouragement in the past. I will give the issue a lot more thought.
Thanks!
As to the extent of rewards inuring to a handful of accounts, this is a chart provided by @aggroed just before HF19.
The figures I cited came from the post where I got the chart, IIRC. Regardless of the mathematical precision of the stated figure, the chart very clearly shows that those figures cannot be far off.
As I recall, @aggroed estimated that after HF19 he expected author rewards to improve such that 93% of author rewards would be captured by less than 10% of accounts.
I have not addressed bots, and do not know how they may be, or not be, contributing to this concentration of rewards in so few accounts. However, HF19 reduced the number of votes requisite to fully draining vote power to 10 from 40, which to me indicates that reducing the manual voting necessary to maximize financial rewards of self voting was the intention, as bots don't care how long it takes.
This would also reduce the necessary number of posts required to make, in order to have posts to self vote, and those posts are not written by bots.
My vote, as you can see, is insubstantial as a means of discouraging the production of content. I do not agree that it represents a meaningful force in comparison to votes backed by $1000's, or $M's of SP.
Thanks again for helping me to better understand these issues.