I think this undesirable outcome is unlikely because a large number of normal users and altruistic whales will bias the final result based upon the quality of the content. If the whale bots win the curation game but lose the quality content game, then all the Steem Power earned from curation will become worthless.

I don't. The "large number of normal users and altruistic whales" won't be able to compete with those bots because of lack of content visibility. To beat whale bots to the trending page, multiple altruistic whales will have to upvote the same content. The odds of multiple altruistic whales stumbling on the same content is already too small and will become lower over time as more users join. The noise level will be too high and the only way to be on the trending page will be to be on an authors' list, even if it's highly competitive.