We have a very sexualized society. It's how we market things. It's why the weather girl on TV is always cute. It's why music has become what it has become. Again, porn is part of that trend, but is not the sole cause of the trend. I think Gramscian Socialism is, indeed, a much better guess at why this got started.
And although society is highly sexualized, feminism and PC norms have made normal male-female interaction very problematic. Dating in college? I don't think I would. Most (not all) of the women I know are harpies -- demanding, angry, sullen, "victims" and really annoyed that they can't find a decent guy.
It's bad out there. It's bad for a lot of reasons.
Porn is a bad refuge from it all, but not a terribly surprising one.
It’s been a boon to the tissue paper industry.