There's several successful 4th gen boy groups (Enhypen, Stray kids, Treasure, TXT, Ateez...), but none of them are really popular outside of their fandom. Some songs may get viral on tiktok but they do not have any real impact beyond that.
During 3rd gen, Exo and BTS had several hits that any kpop fan knew (monster, growl, call me baby, overdose, fire, bs&t, i need u, spring day) and other groups occasionally had hits like ikon, winner and btob.
I could say the same about 2nd gen with bigbang, 2pm, shinee, suju...
They all had songs that were not just popular within their fandom but also outside.
So why is their no 4th gen boy group that succeeded at that ?
We could say the gp doesn't care about kpop anymore but it's not true because newly debuted 4th gen ggs like Aespa and Ive had hits (nl, eleven, love dive).

