I agree with your opinion, especially the last paragraph that says "this division is really theoretical". Sorry, it seems (just of my perception) the originator of this idea just look at the living conditions in their countries that have been advanced. What is the division this generation might be applicable Also in developing countries (can be universal), in Indonesia for example? it that I am still undecided.
I just know , I am an X (= don't care in digital electronics ) ... I don't believe in classification as Socrates once said - "The children now love luxury. They have bad manners, contempt for authority; they show disrespect for elders and love chatter in place of exercise" (goodreads ) , around 2000+ years.
Our kids are us in all their mannerism, the only catch is we (as elders) should connect with their pulse ...
In simple Generation 'all of the people born and living at about the same time, regarded collectively'.
Generation Z are smarter and more prudent than Gen Y. Also known as Post-Millennials, the iGeneration, Founders, Plurals, or the Homeland Generation) is the demographic cohort after the Millennials.
Generation Y covers people born between the 1980's and the year 2000, and these individuals are sometimes referred to as Gen Y, the Millennial Generation, or simply Millennials.
The millennial generation is the generation of children born between 1982 and 2002, some 81 million children who have taken over K-12, have already entered college and the workforce. This generation will replace the Baby-boomers as they retire.
Generation X is the generation born after that of the baby boomers (roughly from the early 1960s to mid 1970s), typically perceived to be disaffected and directionless.