I’m not surprised COBOL is still around. Replacing systems is costly, especially if they work without problems under normal circumstances. There is always something more important.
Not surprising today’s programmers can’t maintain COBOL or other 3rd GL languages. They have never worked at that level of detail. A 2,000+ line program is unreal.
My first app was in PL/1, a combination of COBOL and FORTRAN. It ran for 18 years, but wouldn’t run on newer machines because IBM reversed a property of one data type. They lost the documentation and nobody could fix it. That one program increased the company’s share of the entire market by 20%.
The company finally replaced it when they could buy a package for a PC. The package wasn’t as accurate, but close enough.