Could this be because whales are powering down? That would explain their loss of SP in absolute terms, though you are correct to note the growth of the other classes. That said, for everyone below dolphin, there hasn't been much growth in SP per account, there's just a lot more accounts in those categories.
For example, yes, red fish cumulative SP has skyrocketed by over 1000%. But you do know that there are over 100,000 more red fish than there were a year ago? The average growth per red fish account can't be much more than a few percent.
I would also note that even if everyone below whale-class voted as one, they could not collectively out-vote the whales as a group. So remember kids, if you are trying to make changes around here, you will have to be smart about it.
As for the vote-bots, other commenters have said this, but I'm going to say it again - the 1.7% is misleading. @penguinpablo points out here how much the bots can roughly allocate per day - which seems to be about $22,442.70
(depending on the market etc.). This would mean about twenty grand is allocated every day, on the basis of 1.7% of the votes. I say 'allocated', because the ROI on the bots is so often negative, that the people purchasing these services are not making a profit, so what's really happening is that about $22,442.70 goes straight from the reward pool into bots, and from there a portion of the profit goes back to those who have delegated to them etc.
What you've presented is important, and it's not technically wrong. But unless people follow the reports from @penguinpablo, @statsmonkey, and @bitgeek's excellent payout stats report, they would be getting an incomplete picture of the situation.
I agree with a lot of your comment and upvoted it for that reason.
It is interesting to see everyone's take on the information available.