I'm confident you're actually behind the curve here. The term 'capeshit' has been around for years to express annoyance with the oversaturation of the market with superhero content.
An individual may feel fatigue, but when the general audiences start to feel the fatigue, that’s going to actually make a difference. If there was a superhero fatigue for years, Endgame couldn’t have made nearly grossed ~2.8B USD.
Considering that Marvel movies are not making “all of the money” and are instead making “most of the money” in the eyes of its investors, they may be thinking that the head winds are changing and might want to forestall such a thing.
Of course, there were other reasons that Chapel may have been sacked as well, such as the “Dont say Gay” bill fiasco, as well as having lost their tax free status in Florida,the Mulan controversy, the previously mentioned issues at Marvel, alienating creatives (including publicly fighting one of its biggest stars),underwhelming Star Wars and Disney movies and shows, (possibly) losing the streaming rights for the IPL in India (cause Hotstar in India had a decent chunk of the streaming market in India cause of it).
I'm confident you're actually behind the curve here. The term 'capeshit' has been around for years to express annoyance with the oversaturation of the market with superhero content.