The United States was often compared unfavorably with the United Kingdom, which has one large regulator that oversees all financial services. Here is a simplified diagram of the two countries' regulatory structures (in reality, both countries have a number of additional agents involved in regulation):
That doesn't mean that simplifying regulation isn't a good idea; in fact, it may go hand-in-hand with creating an over-arching regulator to look at systemic risks, as many have proposed. Moving away from regulating based on activity, and towards regulating based on firm, could also help alleviate concerns about products traded "over the counter", that is, not on regulated exchanges like the New York Stock Exchange. However, it suggests that consolidating regulators alone isn't a safeguard against crisis.