Until around March 2021, few people knew about Olivia Rodrigo. She was in some tv series but not a person to be reckoned in the world stage.
However, she became the phenom of 2021, and now BTS has to fight her in an uphill battle.
If BTS loses this round, it will be like the BTS - Billie Eilish fight on 2019 where the latter had taken the throne in the end (although txt did help a lot).
Being a student of history, I have to compare this fight to the DBSK - IU fight in 2011
TVXQ broke into two following a messy fight in 2009, and DBSK returned with an ambitious song, Keep your head down, the success of which would decide DBSK's long term future. (It was used as an OST for a Japanese drama, by the way)
However, Lee Jieun had sung Good Day, which later became the song of 2010s selected by Jeff Benjamin, and the song which basically upset the apple cart in KPop and made the return of the old codgers possible, leading to a 7 year war between SM and IU which ended with the latter's victory on Jan 2018.
DBSK, who probably did NOT know who IU was as late as Dec 09, 2010, had to fight someone whom they would never even have recognized just a few months ago because their stature were so different.
Although DBSK won the fight, they began to emphasize on Japan until this year when Yunho won a #1 in Music Bank (and got into some trouble later).
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BTS - Olivia Rodrigo fight, also featuring Lil Nas X (Just like the DBSK-IU fight featured the actor Hyunbin and also Secret),
is very interesting and if Rodrigo wins the fight it is a not an insignificant blow to bts' world domination.
It is iffy who will win, but cold numbers favor Rodrigo slightly.