There is types of girl crush like Blackpink, ITZY, Everglow.. all quite different from each other.. but I get what ur saying. I feel like there is less variety right now with girl groups than when I got into kpop which is kinda weird cause there is more girl groups. But if you think SNSD, Apink, F(x), Wonder Girls, Miss A, 2NE1.. their concepts aren't really same. Like you wouldn't be able to change songs between them without it feeling like cover. I feel like lot of newer girl groups are lacking identity still or they keep changing it too much so they might lose their identity between comebacks. There is still some with clear identity ofc, but less than in the past.