I've done work with big banks too and share your sentiment.

In fairness some of the challenges I've observed are a result of integrating diverse systems inherited in corporate takeovers. e.g. Imagine unencrypted text files being the "lowest common denominator" to propogate account credentials. I always insist gaps like that are immediately ripped out and fortified, which is usually more a challenge of surfacing the risk to the right exec to get budget to re-engage an obscure vendor to rewrite some component nobody there understands anymore. As a consultant I think I sometimes have an easier time being heard than regular ops admins.