When your only focus is on keeping yourself and children and community fed and clothed, you essentially don't have much time to dwell on things, you don't have the time to be depressed because you need to survive. (That's just my thought, and I don't think it's completely accurate either).
There's usually not enough work for everyone to go around. So everyone only does the bare minimum required to stay afloat.
This is a slightly different aspect than the "poverty" I'm seeing in the US.
Your point still stands though. More time creates more depression, which is why I believe depression in less developed countries would be higher.
