The Ada stronghold is aerospace and defense systems. So these may or may not be legacy systems, but they are safety-critical or mission-critical systems that rely on long standing well defined development processes. That inflexibility means that advancements in the technology are very slow to creep into usage. That goes not only for the languages/compilers but also the silicon and everything in between.
I'm not in banking so I don't know if banks write new business logic with Cobol or merely maintain existing systems. I would be very surprised, though, if modern web-based products are using Cobol, or fancy high-speed trading platforms, or big data-driven machine learning, etc.
