@Foxfyre,
Lets see..
If we look at the chart - prior to 1965, child poverty was higher.
If we look at the marriage argument you made - children were more likely to be in 2 parent households prior to 1965
If we look at the other argument you made children in single family households are more likely to be in poverty.
That leads us to:
There should be more poverty today because there are more single family households.
However there is NOT more poverty.
What caused there to be less poverty?
The largest expenditure against poverty has been by the US government on welfare programs.
The largest expenditure is the most likely reason for something if we apply Occam's razor.
If you have evidence that shows the most likely reason is not the reason, please present it Fox. Otherwise logic leads me to the conclusion you say can't exist.