The tendency of banks to expand their balance sheets, to increase the base of which they generate their income by interest differentials, is driving the level of debts and with that as a direct consequence the level of savings. The US banking system is doing this like nuts for decades now and the US as whole is living on the expense of others by trading the so generated IOUs for all kinds of goods like german luxury cars, japanese high quality products, chinese products and oil. The US is doing that with 88 of their trading "partners" and is in the meantime not only unwilling but unable to deliver real goods in return for this hughe cumulated pile of IOUs aka US$ and US$ nominated (triple A rated!) papers.
While it is certainly a stupidity on the german side to accumulate such amounts of IOUs from someone who is obviously unwilling and unable to deliver real stuff in return, it is the US who enforced the acceptance and savings of US$ all over the place by pushing a so called "Washington consensus" in their own narrow interest.
By the way, the problem created by banks and powerful elites is very obvious on the level of economies, but it also exists inside every economy, where firms and people are forced to accept money created by banks for labour and real things, which end up highly concentrated in the hands of a few (very powerful). The global economy is not a level playing field nor is a single economy a level playing field. There is always a gradient of power which drives imbalances between economies but also inside economies to escalate.
Equilibrium is the pipedream of economists intended to hide this simple fact.
And the banking system is instrumental to create that gradient and to increase its steepnes over time (until things break) and is making an enormous business out of this madness.