I think it's because porn doesn't have so much of a social aspect as movies or music do. So tastes are less regulated by normalization through discussion, which means "movies I can talk about with friends" is an important factor in that industry.

Porn is much more about revealed preferences in isolation.

Almost all "mainstream" porn studios are owned by one company. And they own all the "tube" sites too BTW.

Just a FYI.

A common myth. Mindgeek owns Pornhub, YouPorn, Redtube, Tube8, xtube and Gaytube for tube sites.

They own Brazzers, Digital Playground, Reality Kings, Twistys, Babes, Sean Cody and Men.com for production studios.

There are thousands of tube sites, two of which have more traffic than those mentioned above. There are hundreds of porn studios, many which are more popular than those listed above.

I think it counts when it's a subsidiary of Mindgeek that owns the sites as well. Which is what you will find if you dig into the ownership of most porn sites and studios today.

Not true. I listed the sites that Mindgeek owns above. There are no secret subsidiaries. The porn industry is incredibly competitive, if it wasn't, my job wouldn't be so difficult.