@OpenlyGayExOlympicFencer
Re Alison Steadman, I think that version gets the embarrassing nature of the character dead on, but doesn't display the inherent rationality of her position. Mr B is basically shown as a droll wit, and the irresponsibility isn't there.
Agree -- and Benjamin Whitrow played him naturalistically and appealingly as kind and funny, so we're predisposed to agree with his pov, while Alison Steadman's screamy over-the-top thing, while it nails Mrs B's manner, means we are less inclined to think
she's the parent with her economic head screwed on of the two of them, even if she's going about her project the wrong way,
Her character would have come across very differently had Andrew Davies gone off-piste and included a scene where we see a momentarily steely Mrs Bennet saying in private to Mr Bennet, 'Look, the girls only have a couple of seasons to find a husband while they're young and pretty, and should you die before that, I won't be able to afford to send them to the assembly balls or dress them well on my pittance, and they have no other chance for any kind of financial security, so can we get real here, please?' Or Regency equivalent. 
I've always assumed that the scene in Titanic where Rose's mother talks about women's limited economic opportunities (and how Rose needs to stay engaged to the Nasty But Rich Villainous Fiancé or the whole family will be ruined) is the screenwriters' deeply clunky version of Mrs Bennet's motivation, only of course it makes much, much less sense in the early 20thc.