They're here but they just haven't released any major hits(aside from Dalla Dalla) yet lmao. You can't just expect them to come out of the gate swinging especially when the general public aren't as enthusiastic about idol groups(especially new ones) compared to 2016. Literally the only idol groups that are digimons with the reform nowadays are BTS and BP lmaoo
So in the last 3 years (since people are saying 4th gen started in 2018), they only had one hit? I mean it's not like 3rd gen groups didn't had hits during 2018-2020 so the 'general public aren't as enthusiastic about idol groups' is not a good excuse imo.
But 3rd gen started in 2012 so it took atleast 4 years to it become noticeable isnt it?
I think 2012-2015 in girl groups were transition years which was still dominated by 2nd gen groups and transition groups like AOA, EXID and Crayon Pop. 2016 is the year where new groups TOTALLY replaced old groups.