When I was growing up movies were watched in cinemas. It was a big event and we saw maybe 5 a year.

Over time more start appearing on TV, but those tended to be a bit older, but also cherry picked the good ones. (I don't live in the US).

PayTV didn't appear until mid 80s. They had more movies, but again tended to cherry pick. VHS meant we recorded the ones we wanted to see. All these things together meant we tended to watch "good" movies.

Hollywood of course were making lots and lots of movies we never saw, or had and way to see. The bad stuff simply didn't have a channel to the world.

The arrival of Video Stores changed that. Suddenly the mediocre (and worse) had an outlet. And trust me, there was plenty of rubbish in there. But there was still a cost to distribute.

Today, distribution cost is zero. If Netflix commission a movie it'll get onto Netflix. Regardless of the result. Some really good stuff, most mediocre, lots of real rubbish.

Repeat for Amazon, Disney, Hulu, et al.

Overall movies haven't gotten worse. Objectively production values are higher. But your access to mediocre and bad movies has increased.

Judging past output though introduces survivor bias, which in turn makes comparison to today misleading.