Found this article sad and disheartening but also informative and thought I'd share. I don't know what the solution would be, other than expanding beyond the direct market.
Forbes article link
Excerpt: "While comic shops tend to focus on longtime fans - often older readers who grew up on and collect superhero comics – mass-market bookstores sell to everyone, including younger readers and those outside of traditional comics fandom. Consequently, the books that are selling in bookstores are, generally, not superhero-oriented. According to Bookscan data shared at the conference, kid-oriented comics and graphic novels account for a whopping 41% of sell-through at bookstores; manga is 28%. Superhero content is less than 10%, down 9.6% year-over-year."
Graphics from article: