It seems like the niche that Japan used to fulfill in American subculture is being progressively overtaken by Korea. Not a bad thing, just wondering if anyone else is noticing it.
I don't think it's shifted, it's just gained popularity of it's own. It's not like people stopped liking anime because k-pop exists or something like that. The pop culture of each country isn't mutually exclusive either, plenty of people are interested in both.
No. Korea is just becoming more popular than it was. Japan is still popular as ever.
If you go to YouTube and type in Abroad in Japan you'll see he gets millions of views. Same with Aki,The Anime Man, Cdawgva etc. Their podcast Trast Taste also gets millions of views.
Now compared to a Korean vlog channel it will have very small views.