I think that we are in a stage between recognizing government is a public function and recognizing banking has to be as well.

When those managing the flows of value around the economy and society can manipulate the political mechanisms that should be regulating them, then a feedback loop builds up where power begats more power, until it blows up. Then we try figuring out what we did wrong and try doing it better next time.

The Ancients devised debt jubilees as a circuit breaker for this dynamic, but our societies haven't been stable enough, long enough to recognize the need.