With COBOL it's not just knowledge of the language that's needed, but also knowledge of the underlying systems that old COBOL programs run on. Learning the language would be a valuable first step, but it's my understanding that COBOL knowledge alone will not open many doors.
As far as those "top language" lists go, language rankings depend on who is measuring what, and how they get their data. Some list makers look at languages used in "the real world", wherever that is (business, the Internet, etc), while other list makers take online polls. Expect disagreements between lists.
As far as those "top language" lists go, language rankings depend on who is measuring what, and how they get their data. Some list makers look at languages used in "the real world", wherever that is (business, the Internet, etc), while other list makers take online polls. Expect disagreements between lists.