99-seats-at-Parabasis throws up this chart of TomatoMeter scores of movies from the 1950s to today. His takeaways:
Checking your data set... here's a comment at the website:
This is interesting but also pretty inaccurate. Rottentomatoes doesn’t have a database of every review written about films at their release, so the reviews of films from 1950 don’t reflect viewpoints of that particular period. Of course, the reviews of old classics are overwhelmingly positive– they’re already considered classics! Trust me, after taking enough film classes, there were TONS of duds produced in the ’50s… they just get filed away into the “let’s pretend MGM didn’t just spend many thousands on that rubbish” cabinet.
The cost and scale of what it took to make productions is a worthwhile point to make. In 1950, not only did movies cost a lot, distributing the movie cost a lot of money. In 2000, movies can still cost a lot, but they can also cost a lot less (adjusted for inflation), and distribution costs can be pretty low.
The incentives change: the incentive becomes "let's release this movie no matter what--at least then we can get our money back!"
So what you get is a lot more movies, many of which will be poor quality. Does that mean "movies nowadays suck"? No, it just means there's more, which also means more crap.
I mean, even if you look at 1995, which seems like a poor year -- Waterworld, for Christ's sake! -- it still had Goldeneye and Apollo 13, both of which are excellent movies. I have no issue with the existence of Waterworld, provided that we ignore it. And hey--when that oil spill started in the gulf, we at least saw some benefit from that movie.
Also, it's worth noting that along with the increase in proliferation of movies is the proliferation of reviews. As the commenter above noted, we don't have good records of reviews from then; now, every radio station, online blog, and website has an opinion, and RT casts a pretty wide net. I don't have a lot of data, but I feel from my brief work at StageGrade that it's harder to get an A with 1,000 reviews than with 5.