But what problem would that solve?

Of course it's easy to say "It's their own fault, let them stew in their misery", but that doesn't enhance stability.

The EU isn't about making everybody rich, but it is about preventing poverty to such a degree that people en masse would start to panic vote for the first strongman who promises to fix everything.

If your solution is the same as the anti-EU politicians from a country ("We should revert to sovereign currency so we can print our way to wealth") it's likely not the best solution for the long term interest of the bloc.