There is “popular” and then there is “too popular”. Popular is not bad. There are lots of really good things that are popular.
Like chocolate and vanilla ice cream. They are the most popular ice cream flavors and that’s good. I don’t think anyone would argue that they are too popular.
So what is too popular? Most of pop culture is too popular. The whole idea of a fad or a boom is a bad idea. The things that get popular quickly may not be bad things but by becoming overly popular their status can change and that can be confusing.
Popular things sell well for a long time. Things that are too popular tend to be prone to create a bubble. And bubbles eventually burst.