I agree with you, Line!

Parents can only do so much for their children, whether in Regency England or modern day world. If parents are responsible for the success outcome of their children, then Mr. Bennet and Mrs. Bennet cannot be so wholly bad. A+ daughters Lizzy and Jane (A+ marriages, too). F for Lydia. Cs or Ds for Mary/Kitty. Grade for child rearing would be... 4 + 4 + 1.5 + 1.5 + 0 = 11/4 = 2.75 which would be a C (which is a passing grade!)

Jane Austen did not provide a formula for good child rearing. In fact, perhaps the only good mother (we expect) out there represented in P&P is Mrs. Gardiner.

Another question posed by their very contrast is, why did Mr. Gardiner turn out so well, but his sisters are silly and/or vulgar? Was he educated and his sisters received none? Did they all have also a very silly mother but a father who at least paid attention to his son? And then we have Mr. Bennet who didn't get along with his late brother. And his brother had a very silly son, Mr. Collins. Makes me think that the grandparents in this story were a bit negligent in their child-rearing responsibilities, although we don't know them at all.

And Lady Catherine, for all her wealth, seems to have turned out a rather disappointing daughter.