[exabrial]

Your point is spot on, except here:

> There will be few-to-no kids of poor single moms

Plenty of poor single moms with well behaved kids. The eternal problem is the lack of discipline at home. Successful kids grow up with structure, not being told yes all the time, are held accountable, and have a soft place to land when they make mistakes.

That is certainly harder to do with a single parent home, but it happens all the time in multi-parent homes as well.