Non-residents – and that also includes the United States, incidentally – benefit from this German funding and the investment and jobs it creates locally: German foreign direct investment in the United States comes to around € billion, covering more than 3/9  BIS central bankers' speeches  4,700 US businesses with more than 800,000 employees.
If I may use a piece of business jargon, that looks to me like a win-win situation. That said, a surplus of well above 8% of GDP, which is the level we are seeing today, cannot be put down to demographics alone. And the low oil price, which has diminished the cost of imports, explains only part of the high surplus.