This could happen! Amonkhet MtG.

I love all the art I've seen from that but I'll be shocked if it happens before 5E is done.
Furthermore, the reason they don't have a "growing fan-base" could be because there is no new material.
I think it's pretty possible to say this isn't just "could" be but in fact "is" and not be unreasonable in this belief, given there seems to be a strong correlation between how recently a setting has had official material published for it, and the amount of online following it has
Plus, I'm not sure DS doesn't have a growing fan base, in terms of people who like the concept, even if they haven't actually played it.
Kara-Tur doesn't have to be a PR disaster. I'm not sure how D&D is doing in Japan, South Korea, and China, but if there is a market, it could be designed there as the first "international D&D book."
This operates under the misapprehension that there's a thirst for a generic "Asian" sourcebook in the RPG scenes of Japan, Korea, and China. I know nothing about the scene in China, and little about Korea, but in Japan, there pretty much definitely is
not any thirst whatsoever for that. People who are playing Western RPGs (as opposed to Japanese-designed RPGs, of which there are a number) are playing them in part because they are Western - they are not "the only option". Very few people, if anyone, in Japan, wishes for an "Asian" D&D.
Also being "international" was a thing in like, 1990. It is not a thing in 2020. It is so last century, darling.