In my view, the term "Millennial" (insert air quotes) now defines the current young (< 40 years of age) generation. It also possibly provides some sort of identity to a generation who are disillusioned with life. At the same time people who connect with the term also tend to romanticise life.
Entire bodies of academic study seek to answer "Millennial" problems which trickles down into much hyped Millennial articles. This becomes a positive feedback loop feeding the same cycle. I also have encountered individuals who quote random studies saying this study says millennials like me have the same problems I have.
Therefore, it is clear to me that this particular term is a product of the current era's consumerism culture.
Proponents of consumerist culture generally borrow such terms from the Strauss and Howe generational theory for targeting people in search for an identity.
Therefore my question is,
Are there any records of another such term/s being used in the pre-1900s for advertising? Wherein a part of the population can be identified by demographic/social stratification?
And what terms were generally used?
I would hope not, since people were a bit more busy avoiding diseases and wars.