The sticky backends are still running financial services on z machines and other mainframes. Things running IMS, CICS, DB2, enterprise extender connections, etc. People would be surprised by how much of the financial world is still dominated by these things, although AI and automation type systems work pretty well on this systems.

There are still a lot of mid-range groups running on cloud services in other data centers but most are still interacting with transactional subsystems running on some kind of mainframe.

These mainframes are still a backbone infrastructure for States and cities as well. Capturing multiple workloads from many agencies throughout States too.

Your banking app lets you click pay, while something in-between sends a request to a cobol transaction to create the change and updates a database.

I'd be shocked if they can get that replaced by 2030.