"Macroeconomists Couldn't Keep Up"
"I have a hunch that not a great many macroeconomists paid much attention to all the different kind of credit systems we have. And I can't be sure because I don't keep up with everything they write, but I think maybe the financial markets became much more complicated than they used to be. And as a result, maybe the macroeconomists just couldn't keep up with all of that."
Actually, all you needed to see the problems was Austrian business cycle theory. If macroeconomists had only studied that instead of Lagrange multipliers, then maybe they could have made some predictions relevant to the real world.