I literally said this is gonna happen. Korean is one of the most cheating countries when it comes to international trades. They export a lot but their market is very import unfriendly with some of the worst cases of protectionism.
'Cheating'.
The major issue of domestic/international is being a platform for local interest.
If you had say, Spotify and Apple Music in 2000 (as a hypothetical) ruling the roost in Korea, it's unlikely Kpop even develops into the space it is.
Domestic platforms allows for countries to grow their own market and products. International ones tend to dilute that.
I remember years ago in Australia, there was a dilution of domestic 'requirements' for TV and no regulation on the cable TV allowed. It was a decimation of the Australian film and television industry that'll likely never recover. And there's all sorts of implications on that cohesiveness and culturally.
Koreans are the only country with their language. It's in their own interest to at least be somewhat protective of cultural platforms. And it's hardly cheating. The US does this sort of shit all the time in a massive amount of industries - in fact every western country does. Korean is just looking after one of their major tools of soft power - any leader with 2 brains would do the same.
It's not like the international streaming platforms are paragons of virtue either.