As you mention, it's all about luck regardless. In fact, the previous submission was submitted at an optimal time anyways: http://i.imgur.com/BNCjNwK.png
Actually, for that article, I had made a score histogram for Show HN articles, and it was near identical to the histogram of normal articles. (i.e. Show HNs don't lead to a significant change in the expected number of points). I had removed it from the post because it was getting long. :P
What you're seeing is confirmation bias. There are many, many Show HN posts made, and very few get upvoted.
As you mention, it's all about luck regardless. In fact, the previous submission was submitted at an optimal time anyways: http://i.imgur.com/BNCjNwK.png
(picture from http://minimaxir.com/2014/02/hacking-hacker-news/ )