Comics are in a weird place right now. Single issues barely sell anymore unless it's a #1 or a variant cover gimmick. The real money moved to collected trades and manga volumes.
I run a pull list at a shop in Plano and even they'll tell you — manga outsells American comics like 3 to 1 with younger readers. My niece reads Jujutsu Kaisen and wouldn't touch a Marvel book.
The direct market model is broken. You can't sustain an industry on 40-year-old dudes buying Batman variants. DC and Marvel know this which is why they keep pushing into movies and merch.
I still love the medium though. Some of the indie stuff coming out of Image right now is genuinely incredible. If you're only reading Big Two you're missing the best comics being made.
Manga outselling American comics is not surprising when you compare the value proposition. A $10 manga volume gives you 200 pages. A $5 comic gives you 20 pages. The math is not hard.