I know nothing about China or how pronounced these differences are, but you see the same thing even in the "Millennial" generation everyone loves to talk about here in the US. You'll find a drastic difference between younger Millennials and older Millennials, to the point where Buzzfeed is writing articles comparing the two. No matter how much people want to pretend that "Millennial" is actually a real thing, it's not. It's entirely made up and the sub-generations inside of the category share very different cultural values and life experiences.

It's hard to argue that someone born in 1982 shares much (if anything) in common with someone born in 1998.