...that Henry Austen, if I remember the biographies I have read correctly, was actually providing some money for his sisters' and mother's support, which is not something you can say for Mr John Dashwood.

Furthermore, 500 pounds appears to have been well within the range of what Regency gentlefamilies would live on. The Mysterious H.C.'s post on incomes and status gives the average income of a gentleman's family as 700 a year. Given that this category presumably included families like Mr John Dashwood's with over 4,000 per year, there must have been a lot of other families of gentlemen living on less than 700 a year.

I have a split image in my head when it comes to the Dashwoods. On one hand, 4 people not only not having to work for a living, but being able to afford 3 servants, is a height of relative affluence I could never expect to afford myself. On the other hand, being limited to being on foot (and of course there was no train or bus system in Regency times) would be a very depressing limitation on my life, so I can sympathise with them having to sell their carriage and horses. Plus their servants probably spent something like 90% of their time doing things like washing clothes or fetching fuel for the house, which I do by pressing buttons and turning knobs.