It's posts like these that get me as a programmer worried. Arrogance tends to lead to bad things and the world can change at a pace greater than one can imagine (a good way for me to understand how swiftly things change is to ask myself: Could I have foreseen x years ago what I am be doing today? for me, using the relatively low value of x=5 the answer is a definitive no. And I think that's a good thing).

Be humble if people are willing to pay you more money than others for what you do - it might change incredibly fast. The more generic assumption of the post is that people are willing to pay good money for skills that are relatively rare... well, make sure to keep your skill set up to date.