You're right, the absolute quality level of support structures is not sufficient. The sufficient cause is given by the relative decrease compared to the expectations established in the latter half of the 20th century, which the most affected group (middle class in middle-age, i.e. the majority of Baby Boomers) grew up with as understanding to be an expected part of American life. At least us in the younger generation have a more clear eyed understanding that the safety net can be taken away by greed, and if we ever succeed at rebuilding it, we'll hopefully have the foresight to make it more robust against neoliberal attacks.

> Poorer countries don't have as high a suicide rate

You have to be careful when comparing suicide rates across countries. They often don't count the same thing.