Having studied a lot the matter I can quite confidently agree with you on some of your hypothesis, with the "political idiot" being the most convincing. Overall the "idiocy" was probably well burried under the false hope that the economic parameters of all the countries could eventually converge towards a precise narrow range that european economists theorized.

Nonetheless Italy, Spain, Portugal and Greece parameters defined in some treaties (like Maastricht's) didn't actually fit into the required range at all. In fact, the evaluation that was done at that time focused on the "tendency of the countries to eventually achieve the Maastricht goals" rather than actually complying with them in order to be accepted in the monetary union.

The result was obviously false hope, terrible fiscal policy adjustments and a switch to the Euro currency that could even be considered a financial terrorism act on some countries. An italian politician even messed about for months telling people that "...with the Euro we will rest one day more for every week and earn the same purchasing power...". It's sad, it was basically a political illusion.

Fun fact: the Euro currency was created because was politically unacceptable to use the german Mark as the European Monetary Union currency. I queried some professionals back when I attended mainstream economics courses at university and most of them agreed that the Mark could have been a perfect choice, but was difficult to sell that to european people, so they proceeded with the creation of a new shitcoin.

Fun fact number 2: the switch between the countries own currencies and the Euro wasn't done organically at all...in some countries the currency switch caused a rise of prices sometimes close to 20-30%, because the forex exchange rate fixed polically was not reflecting the actual price levels in the countries.

All-in-all it's been a strange political experiment with no follow-up of any sort, thus the monetary union is not paired to an unique fiscal policy or even to a strong political unity. Not that I was hoping for it, but at least that could have shown some sort of planning in what has been done. No planning at all.