I wrote two pieces about IU's almost impossible challenge against SNSD in Dec 2011.
https://onehallyu.com/topic/41…ite-of-having-fewer-fans/
https://onehallyu.com/topic/58…ght-in-dec-2011-jan-2012/
SNSD had just vanquished its greatest rival Wonder Girls beyond any chance of recovery, and was reigning supreme.
Against it, IU made a challenge, which is still remembered now
With Shinee's Minho and members of Wonder Girls watching, the impossible was done.
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Fast forward 10 years, I have not seen anyone challenging BTS in the last 4 or 5 years.
If someone challenges BtS and falls it, it will probably lead a domestic dominance in Korea itself, although this challenger is unlikely to do too great outside of Korea. It took 10 years to make IU a kpop singer, and such kind of time might be needed for a domestic challenger of BTS.