As Nassim Taleb observed, the problem here is no skin in the game. Bankers keep the upside, but shareholders have to carry the can. It's an agency problem. The fix to all this is dispensing some good solid jail time.
My other suggestion is that to practise banking, one needs a license, which can be revoked. Now that I think of it, Taleb's suggested that banking should be a civil servant job. So, no financial engineering or bonuses, just boring paperwork. In the wake of the financial crisis of 2008 (IIRC), the role of regular banking and hedge fund activities was split in two. The idea is, of course, that if all the fancy derivati…
You are ignorant of current regulation. While there is no paper license that you have to apply for in most cases there is tons of "if you do X you are a Y and must register yourself with some regulatory agency Z and follow our list of rules for your business to be lawful" which is functionally identical to a license.