check the curation rewards for some of the major whales. Bernie sanders was the highest i saw, and his rewards ended up being about one tenth of one percent of his SP balance for the week. Thats actually probably misleadingly high, because he probably probably gets to vote first when he votes for curie.
Smooth made something like .005 percent. dan something like .02%. The fact is, whale voters are the primary thing that determines what content gets paid, and no whale voter that i can find makes enough from curation rewards to be incentivized or dis-incentivized either way.
Bots are actually a huge curation-rewards disincentive for whales to vote for the same people over and over again. Because once they do so, they will start to get frontrun.
You could argue (and it would be a good point, IMO) that the very fact that the effective range of curation rewards is so small is a problem. For example, from a standpoint of just trying to maximize curation rewards, how much effort is it really worth for a smooth to get a couple hundred extra a week return (which is likely about the best he could do) on a half million dollar balance?