Indian and Japanese content were always present but appear to be way more niche than K-content. While I do believe that it has given some exposure to all Asian countries, I also feel like KDrama and movies did blow up for good and specific reasons. Content from India, China and Japan didn't do as well also for good reasons. It's not about the quality of it though, but how much relevant it can be to the countries that find it appealing.
Bollywood does have a special place in the picture but will remain niche. Manga will always be big in the entire world. China unfortunately has more barriers with the rest of the world (not related to content) which directly has consequences on the rest.
Korea appears to have just the right amount of everything, and more than that they produce such a ton of content that it never ends. Being movies, drama, music they are on all front and while they opened the door to all Asia they are also so dominant and everywhere that it doesn't necessarily mean people will massively check the stuff from other countries.
