The article stated "Being technically obsolete gives him an advantage." AND "...there are so few other programmers left who can deal with the old technology! S

The article stated "Being technically obsolete gives him an advantage." AND "...there are so few other programmers left who can deal with the old technology! So...what are good examples of "old technology" that might be interesting and offer opportunity if mastered to fill a niche for the next decade? The article mentioned COBOL. Any thoughts about FORTRAN or particular technical hardware such as old CNC machine tools, etc.?