From 2021-2024, we witnessed the changing of the guard as 3rd gen gave way to 4th gen. Twice, OMG, MMM, RV, Gfriend, and Blackpink were all falling away at various speeds, some declines obvious, others still fighting tooth and nail to top charts. But all unable to stand in the way of the massive steamrollers manned by Ive, NJ, Idle, etc.
However, although 3rd gen groups lost most of their relevancy on Korean charts, the idols themselves still had a shot at maintaining relevancy. Those with the most star power did well on charts or captured GP interest in other ways.
-Jisoo and Jennie still went toe to toe on charts hitting top 2.
-Nayeon shocked the world with Pop, everyone had left Twice for dead but she blew up.
-Hwasa still showed relevancy, even her latest solo did very well, peaking in the top 10ish.
This is what needs to happen with your 4th gen groups. Not right away of course, 4th gen wont fall off the map in one year. But i think the fall has begun and it will manifest more and more in 2025, 2026, etc. NOW is the time to do what Starshit has already done for WY and YJ, what SM has already done for Karina. Assess your most popular idols and find ways to generate GP interest in them, whether domestic like Minji or Winter or Sullyoon or Chaewon, or international like Hanni or Sakura.
I think Idle and Itzy serve as warnings for what can happen if your labels DONT succeed in doing this. Idle is on top of the world as a group, i think they're #1 right now, but the solos for Miyeon, Soyeon, and Yuqi all flopped to varying degrees because both fans and GP just didnt care about them the way they care for the group as a whole. I think Soyeon still has a 2nd chance, her solo released before Idle became massive.
Itzy is in an even worse position, JYP failed MISERABLY in taking advantage of their initial popularity, he had a literal GOLD MINE in Yuna, plus others could have and did go viral like Chaeryeong but it was all squandered away. Not a single solo release in sight for any of them and they are 18 months from the end of their contract. I've seen JYP making attempts recently with Yeji on Sana's show and of course Chaeryeong on Youngji's show but it seems too little too late.
Other labels cant make this mistake. PREPARE NOW, i beg of you, give your best 4th gen idols a fighting chance to survive a post-4th gen world 
