Comment by PeterisP

Instead of overlapping generations, there's a gap of a whole generation of 'mainstream' internet users between the geeky amateurs/dial-up internet which arguably ceases being the dominant usecase already in mid-1990s before the dot.com boom starts due to this generation, and the app users which get seriously started only from around 2010.

Those users were large numbers of mainstream non-geeky people, but they used websites on desktop computers, not through the walled garden of facebook on a phone.