I think "bias" is technically applicable. I.e., the population of older developers is not comparable to the population of younger developers because of survival (or if you prefer, self-selection) effects. Any non-trivial conclusions (e.g., that individual programmers should expect to get better with age, that your company should make an effort to recruit/retain older programmers, ...) from this data are confounded by these effects.
Well, survivorship bias can still be a reason to recruit older programmers - you want the survivors. As for retention, you would hope that a company will know which of their older programmers are valuable.
