BS. While I agree the cutoffs are arbitrary, marking a cohort by, say, "people who graduated highschool before the advent of smart phones" or "people who went through childhood in the early years of social media" are valid groupings.

As a Gen Xer my childhood was soooo different from what kids today experience. And literally every single Gen Xer I know is glad and feels relief (sometimes mixed in with remorse) that our childhood was before the consumer Internet took off.

If you want these cohorts to have statistical significance you have to add more details, such as the geographic location, language, etc. But you can create cohorts with pretty much anything, in itself that doesn’t validate the concept of generations as pitched by marketing agencies