The fact is, the more the euro zone is extended, the harder it will be for the single currency to represent nations which are very different, and the more it will be recognised that it would be much simpler to make the system more flexible by having the euro develop into simply a common currency, overlapping with the national currencies with a degree of flexibility but not replacing them.
Jo mere eurozonen udvides, jo vanskeligere bliver det at fastholde en fælles mønt som repræsentant for meget forskelligartede nationer, og jo snarere opdager man, at det ville være mere enkelt at opbløde systemet og lade euroen udvikle sig i retning af en "alment gældende" mønt, som på fleksibel vis ville supplere de nationale valutaer uden at træde i stedet for disse.