The Euro was a half -arsed attampt at currency union. It left States with too much national sovereignty. If you want to think about currency union then you just need to look at the USA. In amny respects the USA has as much economic diversity as the Eurozone. You have some very wealthy states and you have some very poor states, and the level of political corruption varies. But it's not left up to rich states to decide whether to bail out the indebted states if there is a budget blow out. It's the Federal govt which negotiates with the indebted state. So with Germany holding effectively holding the purse strings it's a situation ripe for holding states to ransom, rather than working out a balanced approach.
Also, Louisianna going belly up wouldn't threaten to cause the whole USD to crumble.
No the Euro is a failed experimaent at currency union while retaining significant economic and political sovereignty. If you want one currency then you have to cede more sovereignty to the central governing power. If you don't like the smell of that idea then go back to national currencies. This half-baked attempt was really doomed to failure from the start.
“The fundamental cause of the trouble is that in the modern world the stupid are cocksure while the intelligent are full of doubt.” - Bertrand Russell
"When the power of love overcomes the love of power, the world will know peace."
Jimi Hendrix
