Also in my experience often tend to be more actually productive, partially by having the experience to avoid more bad ideas/approaches and dead ends. And by on average being much better at the non-typing parts of the job, which are just as important.
One difficulty is that real productivity is difficult to measure quantitatively, especially without putting actual effort into the measurement. Metrics like loc or hours-in-office are fairly meaningless but very easy to measure. Having weak middle/group management (very common in tech, for various reasons) relying on poor metric like this can easily lead you to a negative feedback cycle where you believe you are "better off" hiring a slew of young people, and your metrics "prove" it.
One difficulty is that real productivity is difficult to measure quantitatively, especially without putting actual effort into the measurement. Metrics like loc or hours-in-office are fairly meaningless but very easy to measure. Having weak middle/group management (very common in tech, for various reasons) relying on poor metric like this can easily lead you to a negative feedback cycle where you believe you are "better off" hiring a slew of young people, and your metrics "prove" it.