Too big to fail. Here's an idea: Let's give a handful of firms on Wall Street so much economic power that if they ever fail, the entire economy will collapse with them. Sound good? Of course not. But sadly, that's what Wall Street looks like today, and the problem has actually gotten worse since the financial crisis began because troubled firms have been eaten up in a flurry of mergers with stronger behemoths to stave off catastrophe. With the two types of banking separated, we have a useful banking sector to support the economy even if the Wild West finance hits the skids.