This concept of the value and need for ongoing technical skills development is driven by a misunderstanding of what is truly valuable. Recently on an employment discussion forum, a technologist was bemoaning this fact.
He was asking for input on what skills had the longest useful life. The concern was that the constant grind of learning and trying to figure out what skills were the next hot ones on the horizon was burning him out. What skills, he wondered, would yield a value for more than two years? Many others shared this concern.