The MCU has been around for a decade and a half. During that period, superhero films have revolutionized the way Hollywood works, for good and bad. Lately, audiences have focused more on the bad, leading to what some have called superhero fatigue, factoring into the box office failure of films like the DCEU's Blue Beetle.
Source:https://www.cbr.com/blue-beetle-good-movies-superhero-fatigue/