Porn is a multibillion dollar industry these days. And like any other similarly sized industry, it’s had to adopt a production line mentality. Essentially, you’ve got the same companies, using the same actors, all of them going through the same motions. That doesn’t leave a lot of scope for ‘artistic interpretation’.
No such problem back in the 50s and 60s. Porn was still borderline legal back then and people pretty much made up the rules as they went along. “You want to do what to me?” Also, people actually paid for porn back then – they didn’t just grab it off the internet. With all the books and magazines sealed and under counters, it was down to the illustrator to close the deal with a suitable titillating front cover. Obviously they had access to some real good drugs back then.