Barclays just got fined $453m for manipulating the electricity market in the US, following a £290m fine for fiddling Libor while HSBC is off money laundering with seeming impunity.
A $453m fine for Barclays is equivalent to $600 for the average US household, although if the average US household got caught manipulating markets they'd probably be in jail.
These relatively small fines aren't enough to really change behavior.
Unless we change how the fines are used. Put $453m in an incubator that funds banking startups and you can have 40 scrappy well funded companies trying to take the banks down. A handful of those will succeed and really do some damage. Every time a bank misbehaves it will be sowing the seeds of its own destruction.