I think that’s the real issue. Grownups-with-comic-books is part of the never-ending adolescence you get trying to entertain a society of snowflakes.
You are often wrong but never in doubt: As usual, you categorically and simplistically group everyone in a single unit.
At the turn of the Millennium, I perused, as a personal experiment, the various lists of “100 Greatest Books” and “100 Greatest Movies” of the 20th Century:
My favorite book (excluding the Bible), The Lord of the Rings, did not make any of the lists (it was before the movies made its inclusion acceptable to the condescending intelligentsia), except one, barely, that put it at slot 99 or so. None of my other favorites made a single list. The usual suspects, which I dislike or abhor, such as Catcher in the Rye, made all the lists.
The reason is not, as you so ineloquently argue, because people like me are invariably adolescent or snowflake in attitude.
It often has to do with basic temperament. “Real-life” novels bore me because I already live in real life; I know what it is, and do not need a further dose of it.
Science Fiction and Fantasy appeal to the vividly imaginative minded, not the stolid concretist minded. (See how gratuitous insults work in reverse?)
Lewis and Tolkien cherished Nordic Myth, and shared that passion as academics. An ignoramus like you would have denounced them as adolescents and snowflakes (if they were not, by the bye, famous). (Tolkien also liked science fiction, especially by Asimov.)
Leftism, from Marx on, has systematically eradicated religion and mythology from society. Things like comic books have filled the void. They are often not great, but they satisfy the desire that once was provided by story-telling and myth-making.
Furthermore, movie soundtracks have also filled the void left by the eradication of Common Practice music from the “Classical” repertoire, again a deliberate act by Marxists and Nihilists to destroy natural beauty in music (see Schoenberg, and the Atonalists).
The Captain America trilogy, besides being well-written movies in the genre, had above-average film scores as well. Wonder Woman had a superb film score.