Legalization and decriminalization of Marijuana is still a relatively recent phenomenon. It seems to me like it will eventually get legalized by the federal government. If that happens, wouldn't we expect this to get better? The right thing to do would be to release everyone that was in jailed on marijuana related charges as long as they weren't also convicted of something more serious (like violence). Maybe I'm being too optimistic.
I think a lot of Americans realize how insane it is that we jail more people than any other country. While progress is always slow, it seems like we're hearing more politicians talk about doing something about it.