Converting from (EV on bank accounts) to return for shareholders is non-trivial, but as long as shareholders get > 100% RoI in successful case their EV is positive.
> Bank employees could get higher bonuses, but also run higher risk of 0% bonus and losing their job.
Losing job aside, equal chances of 100% and 0% bonus is better than guaranteed 30% bonus. Depending on premium you put on having the same job, it may be better even with risk of losing job.
This scenario will not work for investments, as people understand that if startup X fails - you loose money. In "government bails out depositors completely" scenario: you invest money in bank, bank loans it to startup X, startup X fails - you get your money back (from government and ultimately taxpayers).