]Over the 7 years, LR never did realize the mistake she may have made.

I find the passage about Anne's refusal of Charles' proposal very revealing, indeed!

She had been solicited, when about two-and-twenty, [...] and Lady Russell had lamented her refusal; for Charles Musgrove was the eldest son of a man, whose landed property and general importance were second in that country, only to Sir Walter's, and of good character and appearance; and however Lady Russell might have asked yet for something more, while Anne was nineteen, she would have rejoiced to see her at twenty-two so respectably removed from the partialities and injustice of her father's house, and settled so permanently near herself.