Those like myself that choose to view dead posts do see these posts. Not everyone will go back to the last time they visited, maybe a couple of pages of submissions. If from my limited background an otherwise dead topic feels it might meet the site's requirements I can then vouch for. Sometimes there are some sites the algorithm or mods have ... put aside ... that vouching does not help, it stays dead.
Given a long term member (akerl_) replied with what I also think is the troublesome domain - that reply has been marked dead - a guess dead just for containing the site's details ... If I were to guess, no amount of vouching would help. I see another you've submitted since, but from my perspective using the ruler of a good member, it does not meet the threshold - it is about converting some video of a lecture the reader has little idea how interesting it might be for them.
HN has some guidelines regarding the nature of topics it would like ... and how to present them. Better results to be had if the lecture topic is something you think HN members would find interesting.
Edit: too much hurry, not read properly ... skimming always gets me into trouble.