Do you really believe that strength of economic theory rests on the assumptions being true. There are theories of consumption that are commonly used by economists that assume that people live forever. They generally do a decent job predicating behavior. It is clearly not the case that people are rationally self-interested. Just talking to people should provide ample evidence against this. Yet the cases originally mentioned are clear examples where a neoclassical economic framework predicts behavior that is inefficient. Further regulation that uses solutions created under neoclassical assumptions generally work quite well as solutions to these types of problems.