I concede that, under some really extreme environmental conditions, any genetic advantages would be canceled out. So, you might actually be right if the IQ 80 mother is really bad. Money should be provided to poor families by the state, but only as long as they raise their child well - as determined by periodic medical checks. Any person, no matter the IQ, can do one thing reasonably well, and that is to raise children to maturity.

But I believe you are taking the importance of parenthood way too far, and disregarding the hereditarian point of view too easily. The blank-slate bias is something to be avoided. I would suggest you read this article by Matt Ridley.

Excerpt:

Today, a third of a century after the study began and with other studies of reunited twins having reached the same conclusion, the numbers are striking. Monozygotic twins raised apart are more similar in IQ (74%) than dizygotic (fraternal) twins raised together (60%) and much more than parent-children pairs (42%); half-siblings (31%); adoptive siblings (29%-34%); virtual twins, or similarly aged but unrelated children raised together (28%); adoptive parent-child pairs (19%) and cousins (15%). Nothing but genes can explain this hierarchy.