Germany looks good now, but when the rest of Europe can’t afford its exports anymore....
Maybe but they will be buying German exports with German money, so this is better? It's a bad situation all the way around. Germany is right to try to stand their ground.
You need to think a few steps further along. You just left things dangling with an ellipsis. Allow me to fill in some of the things your dots imply:
The Euro zone shares a common currency. If each nation had its own currency, variable exchange rates would help return the economies of the respective countries toward equilibrium. They don’t, so one of the most important tools of monetary policy is closed to them. Unless they expel Greece, and other anchors holding everyone else back.
Germany largely trades with Europe — but, it isn’t limited to trade with Europe. Canada’s (mine) Prime Minister Harper proposed an alternative solution — more free trade. He wants a free trade agreement with Europe. (Harper actually promoted austerity at the G8 summit he hosted in 2010 — and he’s now practicing what he preached. Public servants are being fired, the pensionable age is being raised, etc.)
If the economies of other Euro zone nations declines, the value of the Euro will also decline. That would place German exports in an even more competitive position, for trade with the rest of the world.
Etc. World macro economics is hugely complex — nearly as difficult to model as the climate. However, some things are known — the fact that it is a dynamic, adaptive system being the most important. You can’t just think one step ahead.