cobol is trivial to learn. the problem is that the core of old systems were written even before 'Structured Programming' and anything like reviewing and enforcing design standards. there is alot of 60 year old, currently running 'mission critical' cobol, some of it is inscrutable and unmaintainable, while some of it is so simple and elegant that it'd be a great way to teach a 10 year old about programming.
COBOL is also missing most of the QOL aspects of modern languages.
A COBOL system is closer to a bunch of shell scripts coordinated by a master script than anything we might today think of as modular and componentized.
I won't go so far as to say "every variable is global", but it's darn close.
