Rated M for mature

I've been speculating about how the ratings system has changed movies. When I was a kid I saw all sorts of now R-rated films including Midnight Cowboy (hint: not a Western) and The Godfather (at the drive-in with my parents). I think what happened is that with the advent of the R-rating, no reasonable parent would take their kids to an R-rated movie. However, with M-rated movies (which later ended up being rated PG, PG-13 and R) there was a great deal of ambiguity and in that way, more freedom about what kids might see and more freedom about what filmmakers might produce. I think that today, R-rated films are seen as restricting marketability which means that summer blockbusters are now PG or PG-13—essentially kid's movies. But if we still had the M-rating, maybe we'd see more blockbusters like The Godfather. We loved that film in elementary school. I don't know, maybe my memory is totally wrong. Midnight Cowboy was originally rated X but got changed to an R but I somehow can't imagine my friend's mom taking us to either an X or R rated movie. I'm pretty sure that The Sterile Cuckoo that she also took us to (obscure Liza Minelli film) was rated M (and B for boring if you're a kid). And The Godfather may have always been rated R. Well, what do I know? As I say, a bad memory is the beginning of creativity.