So your question seems like pure fantasy to me — like asking how we’ll slay dragons without ads. I don’t know, but I don’t think that’s a thing which actually needs doing, either.
New products within an existing category show up in catalogs, review articles, etc just fine without ads. As does your highly technical product, for which people in the relevant industry already know the information and/or are already used to narrowing their search to a few products and then requesting additional information.
Your pro-ad arguments seem to be solving problems that don’t actually exist.
You make a post on Hacker News titled “Show HN: I made this cool thing called Luminexel, check it out!” Some people will think it’s really cool and tell their friends about it. Eventually it will end up on some “curated list of awesome things” website.
So, place an ad in other words.
Many posts on HN are ads. We’ve just collectively decided that some of them are OK
If you're truly baffled by a view that many people share, you're probably missing something.
How do you solve discoverability, especially of a new type of product or category? I invented this new gadget call "luminexel". People don't know what it is yet, because it's new. How do people find it in a catalog?
Or the thing I sell is fairly technical and needs more space for descriptions / photos to communicate what it is. Do I get more space in the catalog?