Correction to you correction. I didn't say the things you seem to be inferring and/or implying I did. I said "wonderful" not "perfect" and I never claimed it was all that 3PP need to connect them to potential customers.Correction: Google is an imperfect tool. Appealing to it as all that a third-party publisher needs to connect them to potential customers comes very close to saying that advertising and marketing are pointless, since said potential customer base will always be able to find your stuff simply by Googling the theme(s) that they cover.
Naturally, even a casual examination of the topic should make it clear that's not the case.
To address some of your other points... just as a search isn't 100% let's not act like your marketing (especially that available to a 3PP ) will always result in a potential customer connecting with a company that produces what they desire. Nothing can guarantee that. D&D is literally the largest ttrpg in the world and there are still people who are just finding out about it today. One of the aspects a business deals with is bad press... If you go into a business that holds a certain stigma you should be accounting for that stigma in your projected sales, targeted marketing, and internet presence... if you don't well that's on you.