I recall reading that somewhere (maybe Pottermore?), Rowling said that the Malfoys gained their great family wealth by trade with muggles, until the establishment of the statute of secrecy, at which point they were quick to join the "Yep, we knew those dirty muggles just wanted to exploit and burn us all along!" crowd. I don't remember if there is any similar detail about other wealthy families in canon or MoR; there's Flamel with the Philosopher's Stone, and the Potters with a combination family inheritance/bounty on Voldemort, but the Malfoys appear to be decidedly the richest family in Magical Britain, and I'd imagine that even with a 400 year gap, being those to most thoroughly exploit trade with muggles would be more than sufficient to explain their success.
This is a new thread to discuss Eliezer Yudkowsky’s Harry Potter and the Methods of Rationality and anything related to it. This thread is intended for discussing chapter 97. The previous thread is at nearly 500 comments.
There is now a site dedicated to the story at hpmor.com, which is now the place to go to find the authors notes and all sorts of other goodies. AdeleneDawner has kept an archive of Author’s Notes. (This goes up to the notes for chapter 76, and is now not updating. The authors notes from chapter 77 onwards are on hpmor.com.)
The first 5 discussion threads are on the main page under the harry_potter tag. Threads 6 and on (including this one) are in the discussion section using its separate tag system.
Also: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25.
Spoiler Warning: this thread is full of spoilers. With few exceptions, spoilers for MOR and canon are fair game to post, without warning or rot13. More specifically: