I've wondered along the lines of your question. So I was hoping to find more information. Totally agree with you, that there seems to be a huge factor of "luck" involved in using HN to promote products.
Since I was very curious about your situation, I checked your profile, past posts and comments. Whilst my comments don't directly answer your question, these are the things that stood out for me:
You have been on HN for over 8 years and in that time you have only amassed 107 karma. That immediately signals to other HNers that you are not a particularly involved member.
Most of your posts and comments have a "marketing slant". HN is, IMHO, a technically oriented forum. I often notice a certain level of hostility towards posts made by sales people, recruiters, etc. For me you would have more "impact" by contributing to various technical discussions.
Looking at your two products and the comments on them by other HNers suggests that they are not as "exciting" as you think. There are thousands of products (I use the term very loosely) out there. You have to make your stuff really stand out, capture interest and of course a huge measure of luck.
Finally Show HN is but one of potentially dozens of avenues to promote your products. Perhaps identifying forums that deal with your application area is useful. I know some people who are very active in domain specific forums on LinkedIn, thus they have a certain profile. They then in turn contact other active persons on the forum to canvass for business.
I hope my comments will provoke some rebuttals. My comments are just one data point. You need a broad spectrum to base any decisions upon. Good Luck.