Good movies aren't created often, while movies in general are now produced more frequently, so unimpressive movies are much easier to bump into. I just saw a chart showing over twice as many movies were released in 2018 as in 2000. It would be interesting to see for each IMDB decade what percentage of films are rated 8 or higher.
> movies in general are now produced more frequently
I don't agree with this. Blockbuster used to be filled with movies made to go straight to "home video" whether that was VHS or DVD. Shitty movies have been made for a really long time. Typically, they didn't have a budget and no studio was involved. Now, we have really shitty movies with incredible budgets being released by the studios as well as whatever the streamers are making. The straight to home video market does seem to have lost a bit though as they still need to find a streamer willing to license it.