Wandering Along the Path: Right Speech

My husband and I have been distracting ourselves from the smoke and cabin fever by watching "Pride and Prejudice", both the long Colin Firth one and the short Laurence Olivier film.  We discuss the merits of each version, the acting, and the impression each leaves.  We both liked Firth and Ehle, but my husband prefers Olivier and Garson.  We love the short film's happier tone and lightness, but the last third is totally inaccurate to the novel.  Though we love that Lady Catherine, she is not recognizable from the book, with her abrupt about face in approving Elizabeth.  The BBC film is much more accurate and fills in many important plot points left out of the short film.  The former is much darker and the later comedic.  I am a stickler for not overlaying modern interpretations on the novel, and so I do find the BBC film more faithful in intention to render a perfect novel perfectly.  But as I say this, my one quibble with the novel, and both films is Lydia's and Mrs. Bennett's ignorance of what Lydia's elopement means to the family.  I can only conclude that Lydia is a sociopath and her mother amazingly stupid.  Something about that device of the elopement and Darcy's rescue to redeem the family is so implausible as to be a glaring fantasy.  I'd have asked Jane to change that plot point and invent one that is more in the whelm of possibility.  What?!  Edit Jane Austen?!  Cabin fever indeed!