As someone who read those old Marvel and DC comics, and who learned storytelling and world building, there are only so many things you can do. And while the costs for special effects for TV have come down, the concept designers still need to get paid for props and sets. Comic books never had that problem. The data-driven number crunchers, or bean counters, decide what stays and what goes, and test to find out what the audience prefers. I come from a generation that was not raised by the internet, we went to libraries, and we had many face to face occurrences and friendships. This current media generation of creators have a much narrower vision by default.
TLDR. I’ve been reading a wide range of things all my life. Sitting down with a book about a subject you know nothing or little about seems counterintuitive. For some, the internet is everything, and “we can’t do it the old way because it’s old.” I know people who work at Marvel and DC. I have no interest in current comic books.