] I understand the point, but must observe that the Bennets aren't that wealthy. Certainly they would wear their best white outfits for major occasions, but not for "everyday" as they seem to in PP2.

Check out Jack's message linked below. The estate is entailed away, but as long as Mr Bennet is still alive they have a good £2000 per annumn, and that's rather wealthy for the time. They've a estate, a butler, a cook and a housekeeper. I'd estimate they'd have two or three house-maids, and quite possibly send their washing to a washer-woman. We need to remember that the fashion was for light dresses, and Mrs Bennet certainly wouldn't have let her daughters be unfashionable in sensible clothes.