As for the banking bit. You are missing my point, nobody builds a bank because of the technology, people found new banks because of the money. If that means adapting old, tried and true technology to jump trough new hoops then that's a cost of business. Bankers are conservative by nature, not because they like it but because it makes very good business sense when you're a bank. It's no coincidence that banks, insurance companies and governments are the areas where the mainframe is still dominant.
I'm really not sure what kind of services you could offer with a 'new' software stack that you could not offer with the old one. Bank transfers are routinely done in seconds between banks, you can pay with everything from credit cards to mobile phones and computers, they seem to have done a remarkable job at adapting to new tech while remaining conservative at heart.
People hate their banks mostly for the costs and for the lack of human interest, rarely if ever because of the lack of technology. In fact, I could do with less technology and better human interaction.