"and also some dogs"

He's right about the "back in my day" angst and the constant distrust between generations.

But just because "generations" are a construct doesn't mean they're necessarily invalid. Lots of things are invented human constructs, and still useful.

Historical periods, eras, or epochs are also constructs--e.g.,the Middle Ages, the Renaissance, the Enlightenment. But they're constructs we use to make sense of vast data sets across time by subdividing them into digestible units based on certain temporal commonalities and the general point at which these commonalities experience a shift.

We do the same for groups of people, usually setting the divisions on "big events"--WWII and Vietnam, the rise of home computing technologies, 9/11 terrorist attacks, etc.

We use the constructs because they are useful subdivisions, not "perfect" or "natural" ones. The issue is when we start reading more into them than is there--like computers make people lazy, just like calculators, photocopiers, fax machines, typewriters, or any other communication/information technology made anyone before us lazy.