Mr. Bennett apparently suffered from the economics "Law of Diminishing Returns" where the attention went to the older daughters and diminished as it reached the younger daughters. Whereas, it should have been more efficient not "sillier."

I, too, was surprised that the Bennett's did not hire a governess for their daughters. However, with Mr. Bennett staying in his library and Mrs. Bennett preferring to stay home, this is what they end up with. I suspect that hiring a governess would have seemed like a threat to the household. The governess may have introduced higher intellectual standards into the Bennett lifestyle that may have suited Mary more than anyone else. I would surmise that Mrs. Bennett would not have wanted this type of competition in her own home.