When I first began to acquaint myself with the Regency time period, I learned that relatives, brothers in particular, were expected to be responsible for helping mothers and sisters when the head-of-household passed without leaving sufficient provisions for them to live independently. If this responsibility was ignored, they would lose the respect of friends, neighbors and family.

Then I got a copy of The Cambridge Companion to Jane Austen and read this:

...virtue goes unrewarded, that ingratitude, caprice, and selfishness prevail, that people do active harm and yet remain respectable. The Dashwood family had lived for generations 'in so respectable a manner, as to engage the general good opinion of their surrounding acquaintance'; and John Dashwood will clearly not lose the good opinion of his neighbours by leaving his dependent female relatives penniless.

So there you go. Mr. and Mrs. John Dashwood have in effect inherited the respect already earned by former generations. John Dashwood need only say that he offered his home to his mother and sisters, (which he did), and they chose to leave. He's certainly not going to volunteer the information that he reneged on his promise nor that his wife didn't make them feel very welcome. As already stated by Rachel, it's a matter of maintaining an outward respectability. If the Dashwoods had stayed in the area living in genteel 'poverty', this may possibly have lifted some eyebrows but... Things just seem to work out for these two. :(

I wondered about Fanny and her personality, if she would fit in well with the surrounding families. It occurred to me that her nasty attitude is reserved mostly for those she considers to be beneath her or are a threat to her family name or funds. I'm sure she'll have no problem.