"that the US has only become an optimal currency area in the past 30 years or so - it being the growth of the federal government that has made it so. Pre-WWII, the Feds were really pretty piddly in size compared to the States."
WW II ended rather more than thirty years ago. To be sure, I can remember some very odd dealings in the 1980s when so many thrift institutions went bust, but that much odder than went on the bubble of 10 years ago. Indeed the federal government was much smaller before the world wars, but the state governments were not that large.
And if you're going to give us the School of Athens, shouldn't we have Angela Merkel as Plato, pointing up to indicate the size of the debt, and Varoufakis as Aristotle, pointing down to show where the Greek economy is?