This is strongly contradicted by how frigging long movies have gotten. Old action movies are often in the 90-120 minute range. New action movies - that are supposedly lacking that old filler - are often 3 hour slogs.
https://towardsdatascience.com/are-new-movies-longer-than-th...
But here again we're looking at Marvel movies and saying that's the entirety of what's being offered in cinema's these days. It's not, but it feels like it.
But there is no general relationship, direct or inverse, between the length of a movie and the quality of a movie. Some movies should be short and some movies should be long. It really depends on the movie in question.