Having worked in banking for many years (no longer), I can say with confidence, the big banks have a giant moat: regulation.

They want to be heavily regulated so that new upstart competitors will not come in and spoil their cozy space. And it’s easy to justify because terrorism, money laundering, insider trading, etc etc. And many of these regulations are largely ineffective and easily worked around, whilst costing billions to the banks to comply with. Hence the moat.

We won’t get banking disruption until there’s banking deregulation.