Korean vocalists aren’t popular internationally either.

It is the stage performance of dance choreography, production features set to highly danceable music with quite some English thrown in and a culture of extreme beauty consciousness, fashion and most importantly fan service — all aggressively marketed, that has pushed K-pop to the West. (not that much the world).

Koreans have to do that because.S.Korea is a very small market with a population of 50 million.

Whereas most states in India themselves would have more than 50 million.

And then there is familiarity, K-pop’s origins and sounds are from the West, so West is already familiar to much of the sounds and can relate.

The same with India where Bollywood can be heard from Morocco to Indonesia or its influences. But not that much in the West.

So the reason is not the “talent” of the artists, but cultural familiarity, business model etc.