[IsaacSchlueter]

> Since I don't see this specifically addressed in the text: I suspect this is a classic case of survivorship bias.

The text didn't seem to do much besides present the stats. But he say this:

    I knew that with age coders tend to switch careers, but I
    was surprised to see the size of the drop. After the peak
    age of 27, number of developers halves every 6 to 7 years.

I figured that "survivorship bias" was sort of the exact point he was trying to make. Beyond that, there's really no discussion of causation (getting older makes one more "mature" or whatever), so I think it's implied that weeding out less committed devs is exactly what's going on.