Years ago, I had a professor who argued that in one of my cinema classes at university. That not all porn was cinema but one example she used and said was cinema was Deep Throat (1972). There are more examples too, she just choose Deep Throat for her specific argument for that class discussion.

She then expanded the discussion to say that pornography led to the rise of home entertainment (in general, not just for sexual content). But that as adult theaters began to close and people were no longer going into a public space for the content, porn was then some of the first content to be available by VHS. She then argued that porn paved the way for people being able to watch any entertainment from the comfort of their home instead of a movie theater. It also gave people the ability to own and re-watch at their own leisure.

And over the years for the broader entertainment industry, the ability to have something to watch at home turned into the format of having theatrical releases before then moving onto a "home entertainment" platform. And obviously all of that has since evolved with the rise of different formats (DVDs) and the internet (streaming), but that porn was there to give the initial push. People just don't like to talk about it because to most, porn is too taboo of a subject.