This comment seems to be more about putting all your eggs into one basket than the idea that every technology is going to die in a few years. Most of the popular production languages today are 10+ years old, for instance.

Not every technology, but rather random technology from the set of things-which-currently-look-good-when-seeking-work.

Important difference.

For example, at one extreme, all tech lasts exactly three years; at one of several other extremes, 50% of tech is eternal and the rest lasts exactly 1.5 years.