The truth is that the only thing that kpop does better than jpop is international promotion, because the music ... I mean, Korea only lives on idol groups, and I think that only one group represents 40% of the value of the Korean industry , what a mess
I'm familiar with jpop, personally I liked jrock more (but older jrock).
At first, before I really knew K-pop, I thought it was as uninteresting (to me) as jpop, but then I got to learn more about K-pop, and I found it a hell of a lot more entertaining and appealing to me than j-pop.
And from its worldwide appeal, I can see I'm not the only one.
It's not for nothing that j-pop has nowhere near the global appeal that other Japanese entertainment genres like games, anime and manga: it's simply because jpop fails to live up to the high quality and entertainment standards that those other Japanese entertainment fields have to offer.
Basically it's a huge, structural failure on the side of jpop as an entertainment field, and it's not because a lack of promotion.
These are flaws that K-pop doesn't have. Which is why K-pop is doing as great internationally as other Japanese entertainment aside from J-pop are doing.
Even before and without BTS, the K-pop industry has been thriving a lot more on an international scale than j-pop ever did.
Like said, the failure lies with j-pop itself, it just isn't on the quality entertainment level that K-pop, anime, manga and Japanese games industry are, and which make those other entertainment genres more appealing to the rest of the world.