It’s natural for countries to be different. You can’t blindly copy whatever another country is doing and expect the same results. The manga/anime industry in Japan has boomed for decades, yet so far no other country has the same manga culture or is able to replicate Japan’s success in that space internationally (maybe with the exception of the US, but American cartoons and animation films are very different from Japanese ones.)
The same is with Hollywood—the US dominated the global film industry for decades, yet no country is in a position to challenge that.
Now, it doesn’t mean that Korea and China are doomed in terms of cultural exports. Korea had a pretty successful strategy of promoting the K-Pop industry, and we’re already seeing its successes. Korean singers, bands and dramas are being consumed as mainstream entertainment in Asia, and maybe beyond. The Chinese government is a lot less active in the promotion of cultural industries, but even so we’re already starting to see the consumption of Chinese entertainment abroad. For example, Genshin, a Chinese game, has been topping the charts on mobile platforms across the world. And of course TikTok is a Chinese company.
I think it’s fair to say the both China and Korea were steeped in Japanese popular culture (even more so than the west) and now they’re incorporating it into their own cultures and products. It’ll be a good thing for the world to have a diversity of cultures and approaches.