Why were pure-blood families like the Lestranges, Malfoys and Blacks rich, but the Gaunts weren’t? I can understand why the Weasleys weren’t rich. It’s implied they had more kids than they could comfortably afford, and both the Sorting Hat and Aunt Muriel mention how huge the Weasley family is. There were so many Weasleys that nobody even seemed to know how some cousins were related or why they’d never met them. But if we’re saying the Gaunts interbred so much that they eventually lost their sanity while trying to preserve their bloodline and wealth, why wouldn’t other old pure-blood families have similar problems? What actually made the Gaunts different?