A woman friend dropped out of IT, to be a full time mom for 14 years. When she was about to start job hunting she told me that Se thought she had become unemployable. She was working at a bank within a week, making mint.

She told me that the primary reason they kept those systems working was that banks and insurance companies could not afford to do a migration where a small mistake could cost billions.

Also, I've done cobol in my day, and it's really good for these kinds of applications.