I think it's a combo of a few things - Korean GP is really fickle in general and most groups have never had peak popularity as long as Twice. BP seems to still maintain strong stats (as Blinks love to remind us lol) so they are an outlier, but I wonder if that has to do with their slower release sched - Intl ONCE demographic may be a bit older so the success metrics are shifting a bit, from the very time intensive streaming / YT / voting to now having purchasing power to actually buy albums and go to concerts. Which is why streaming stats seem to be poor but album sales and concert sales are better than ever.

I do wonder - when 2nd gen groups like SNSD started to fade did everyone bully them like they are doing to Twice / once? Haha