Originally posted by Zack M
WB's divisive films certainly doesn't help, but the fatigue was there before that, which is why AOU made much less than the First Avengers.
The first Avengers was a first of its kind team up movie. Multiple films in the same universe and then having an ensemble movie was not going to be matched again to that effect.
The wow factor of the first Avengers was gone butt Age of Ultron still did massive numbers.