This has never been an argument when it came to putting groups like EXID and EXO in the same generation as Blackpink and Wanna One, so I don't know why it should be an argument now. Besides, the divide in generations is a lot more about the methods of promotion as well as the shift in target audiences (with BTS and Blackpink being the main initiators of that) so to me it makes perfect sense for all of those groups to be 4th gen.
I brought this up probably six months ago and you shot it down immediately, and then in your absence probably a half dozen other users have echoed the same sentiment.
The zeitgeist HAS changed, and we've seen a whole slew of new groups debuting with a pared-back aesthetic/minimalist sound. If that doesn't constitute a new generation
to you, that's fine, but there's been an undeniable artistic shift in this new cohort of rookie acts.
"generations" seem to be really loosely defined. They don't seem to have any real start or stop dates. Also, generations seem to be getting shorter. Generation one seemed to last for 15 years while generation 3 seemingly lasted for only about 5 years before gen 4 talk started.
And I co-sign this. Since the Big Three aren't the only ones making waves these days, the idea of "generations" isn't really tethered to the life cycle of their respective groups. Gens three and four were already
way shorter than one and two, and k-pop is (continuously) hitting new levels of global saturation, so it's no surprise to see a new trend arrive in this current moment in pop culture.