It may be an "old cliche", but also happens to be true. Maybe you can quibble over whether it's a 10X, 100X, or merely a 5X difference, but some programmers are clearly much more productive than others.
It's also true that some programmers are more productive collaborators than others. (In fact, some are effectively anti-collaborators -- less work gets done when they pitch into a project.) If you are in a collaborative enterprise, this might be something to consider.
