MILAN – Over the last 20 years, roughly a half-million Italians aged 18 to 39 have moved abroad, especially to more economically dynamic European Union countries such as Germany, France, and the United Kingdom. And those are just the official figures; the actual numbers are probably much higher, possibly more than double. Why are young Italians so eager to leave?

It is not for lack of political representation. Since 2013, the share of Italy’s parliament that is under 40 has increased from 7% to...