Exactly, and further to that there's got to be a number of facts influencing votes on posts from a particular author as time goes on. A follower may get sick of your style or simply move on, or decide they don't like you any more due to some edgy thing you post or even the way you say something, for any kind of other related behavior like supporting or opposing the whale experiment, or similar. The follower may have a personal change in their life, temporarily or permanently leave Steemit, power down considerably or change their bot algorithm.
You really can't infer quality from votes! There's just too much going on.
And thank you for the complement, it did take some time to compile and think out! 😄
You are welcome. I could see it was a thoroughly researched piece!!