COBOL has stood the test of time, because it adheres to a self-documenting, structured programming standard that was born by a demand for custom software quality and portability across vendor platforms.  By sticking to this standard of openness, COBOL gained wide acceptance and became the most widely used programming language in business with a commanding majority in lines of code written. 

Modern COBOL is Object Oriented and Recursive, just like Java and C#.  Improvements are slow to arrive because they are made by committee not by a single vendor.  That is how COBOL distinguishes itself.  It does not rely on buzz words for sales.  It is readable.  It does not change so readily.  It is reliable.  The alternative is undecipherable code and unproductive programmers who are bent on job security.