This is exactly why this analysis is constrained to 'generally speaking', and why there is no commentary on individual post data.
It is impossible to determine causation with any degree of certainty. For instance, this post was promoted too, and just recently upvoted by both Ned and Dan. However, how could I know, with high degree of certainty that the exposure from promotion brought them here? What if the post was actually referred to them by someone else, who saw it in steemit.chat, or is perhaps my follower, or someone who just likes to scroll trough entire trending page every day.
Given the lack of information, any 'evidence' to support a case would be anecdotal at best.
Perhaps with due time, as the sample size grows, we could infer some patterns. Right now however, we simply don't know.