The people who would do this are not on the Wizengamot: Maybe this does happen. Perhaps all the muggle-born realize how easy it is to live a life of luxury in the muggle world and do exactly that, and only venture into the magical world when the want to go shopping. They have the best conveniences of both worlds and none of the dangers of either. This... actually sounds kinda plausible. Plus, there isn't a great job market for muggle-born.

Like going off to live in a poor country if you have a first-world income to live on. I believe it's already been remarked that this is about how magical Britain views muggle Britain.