Well, it's not that downbeat, but nonetheless Leo McCarey's Make Way For Tomorrow is one of the saddest movies ever released by a major studio. It's the story of an old couple (Victor Moore and Beulah Bondi) who can't afford to keep their own house any more; none of their children will make room for both of them, so they go to separate houses. At the end, Bondi is shipped off to a nursing home while Moore goes to stay in California; the couple spends a last day together in New York -- the first time they've been there together since their honeymoon -- and then they part, knowing that they'll never see one another again. The end. No uplift, no action, not even really any villains that we can have the fun of hating (their children and in-laws are ingrates, but they're not portrayed as evil, just selfish in a very conventional and familiar way). Though it's a sentimental movie, McCarey doesn't sentimentalize the old couple: they're not wise or brilliant or particularly lovable, just a pair of fairly nice, somewhat irritating old people who don't deserve to be forgotten and discarded.
The scenes I'm linking to here -- I posted another scene from the film on YouTube -- are from near the end of the film. First, after a scene with Thomas Mitchell (as the son who's just made the decision to send his mother to the nursing home), Moore and Bondi spend the day in New York -- with, unfortunately, some really bad back projection -- and meet a car salesman who turns out to be very compassionate and nice; it's a running theme of the movie that the couple gets better treatment from complete strangers than they do from their own children.
The next scene has Moore and Bondi at the hotel where they spent their honeymoon. (In the middle of the scene, Moore gets to call one of the kids and finally tell them off for the way they've treated him and Bondi.) The scene showcases McCarey's favourite way of doing a scene: keep the camera still, don't cut much, and let the actors improvise as much as possible. McCarey's love of improv and ad-libbing, which started in his days with Hal Roach and continued right to the end of his career, makes the acting in his movies seem very natural; an actor like Moore, who was mostly known for his stock comic mannerisms, is very real and un-mannered in this movie. The way McCarey made movies can be summed up like this: you know the famous out-take from Apocalypse Now where Marlon Brando says "I swallowed a bug?" McCarey would have left that in the movie.
This is a film that's never been available commercially on home video in any format; it has no stars and not much name recognition. But it's a great movie; it does what Tokyo Story would do 16 years later, but in some ways it's a richer and more interesting film. McCarey was upset that he won the Oscar for The Awful Truth that year instead of this one; all I can say is that his output in 1937 has to make that one of the best years any director ever had.