I am not a lawyer but but I have worked for a bank and one obstacle I could see would be the legal obstacles of 3rd party data processors. Some or most banks w

I am not a lawyer but but I have worked for a bank and one obstacle I could see would be the legal obstacles of 3rd party data processors. Some or most banks will have contractual and regulatory requirements that prohibit 3rd party data processors in certain circumstances. Proving and auditing specific data flows are kept out of the 3rd party is overhead and risk. I could see some banks just avoiding that overhead and risk all together. One work around could be if the bank acquired a cloud provider which probably explains why so many banks are running VMWare.