People are keeping money in banks because of no choice,because they are getting his salary via bank transfers to his accounts.Even that there is 10 mln unbanked people in USA.Just some days ago we had big 50bln repo .50 bln dollars was injected in banking system because of no liquidity.Similar was in 2007.What happen next we very well know.Last time there was 20 bln dollar Russian money laundering done by big banks from USA and EU
There is possible to add even more to that list.But banks are still sacred cows and they can always count on Central Banks help