Thanks for the insightful comment!
No honest Block Producer can offer all of their rewards to voters
I disagree, because it's kind of already happened. A year or so ago, the witness reward was so small (as steem was something like 4-6 cents) that ALL witnesses were operating at a loss compared to the fair market value of their CPU time. So we've already seen it happen before. Further, I was actually one of these witnesses, and if you ask me if I would do it again, I'd probably say yes -- I believe in Steem as a disrupter of traditional systems, and I would be willing to support it once again for free if it came to that. But for security reasons, I also think it's quite dangerous to have that situation occur. So I have mixed feelings on my food for thought question about "what is the correct reward to give?"
What you get into the second part of your comment I kind of cover in my 'reality?' section, and I basically agree. At some point people will hopefully weigh their long term interests (of value security) greater than their short term interests (of immediate financial reward). Unfortunately, you have to believe that everyone else will also understand and evaluate intelligently and rationally all of the risks -- and they may not do that if they believe they can skirt the edges and line their pockets.