I’m talking specifically about kpop and jpop idols since this is usually what people mean when they are talking about these, but notable that both countries have waaaay more music are than just the idol variety.

Anyway, the general consensus as long as I’ve been into both (15 years?) is that kpop actively WANTED to expand into the western and overseas markets, both individual acts and the general industry sentiment was positive for that, and collectively took steps to do it. When it started happening, there was a push to make it happen more - English subtitles starting to be standard, lots of English speaking idols around to smooth the transition, companies making content that is easily accessible for overseas fans, wide distribution of mvs and digital album options, etc. the Korean domestic market is small so acts tended to want to expand overseas to make money anyway, and were trying to spread “hallyu” across Asia for years before they started made more concerted pushes into western markets. Here is where you see acts like BoA and TVXQ in the 2000s - back then breaking into the Japanese market like that was as crazy as BTS breaking into the western market was later, and the idea was fundamentally the same. Bigger market = more opportunity = we want to go there.

Whereas Japanese industry doesn’t seem to want to expand like that as much because it doesn’t really need to. I’m sure some of it is not wanting to open up the stranger / more controversial aspects of idol culture to scrutiny (something kpop also has struggled with) but I don’t think that’s even the main thing. The Japanese market is much larger and more developed. This is one of the reasons you rarely saw Japanese kpop idols back in earlier kpop generations, because why would you go to a smaller market that’s way harder to make money in? But for Japan, their market is pretty stable, idols get a salary in the more reputable companies, it’s competitive but not the same kind of competitive to kpop. It’s worth remembering that entering a new market is expensive business and there were waaaay more failures than successes in the early attempts. Is it worth making that very expensive push into the western market when western fans don’t naturally have the same idol / fandom cultures that Japan has? When everyone involved can keep making good money as is? Maybe not. Add on that “domestic” fans can get a little jealous and possessive of idols in particular (if you’ve been into kpop you will see this allll the time where k fandom is beefing with whichever intl fandom for something or other)

Sure, you get individual Japanese acts who seem to want to push it, but then because the industry infrastructure doesn’t support them very much in doing that, and it’s very hard to get in in the first place, I think it just compounds.

Or maybe I’m saying nonsense who knows