Ultimately it’s about the audience and what they want to consume. That has changed over time, and along with the increasing polarization in our politics, our interests and tastes in how we are entertained has also become polarized. It’s all a reflection of an ongoing cultural divergence, which results in people judging others, and their creative product, as good or bad.
There’s also the matter of gatekeepers, those who decide what we get to choose. They will always lean toward what is popular in the moment, because that’s where the money is. It’s always been that way, though.