Welcome to Europe, 2021. Ten years have elapsed since the great crisis of 2010-11, which claimed the scalps of no fewer than 10 governments, including Spain and France. Some things have stayed the same, but a lot has changed.

The euro is still circulating, though banknotes are now seldom seen. (Indeed, the ease of electronic payments now makes some people wonder why creating a single European currency ever seemed worth the effort.) But Brussels has been abandoned as Europe's political headquarters. Vienna has been a great...