@Rayster " the quality of Korean-manhwas pretty much surpass Japanese-mangas' already" It might feel this way because only top korean stuff gets translated, while in japanese we get a lot more average and bad. Doesn't explain bazillion of translations of chinese cultivator manhuas (a lot of which are trash tier), though. Basically there might be novelity factor.
For example, compare "Solo Leveling" to "I am the Sorcerer King", "Tomb Raider King", "Rebirth of 8th circle wizard", "Skeleton Soldier Couldn't Protect the Dungeon", "The Gamer", "Hardcore Leveling Warrior", "Dimensional Mercenary" or...
How about "Monster Duchess and Contract Princess" vs "I'm a child of this house" vs "Lucia" vs "The Duchess with an Empty Soul".
There's also ton of high sexual content manhwas which do not exactly have the best story.
Basically... they still reuse each other's stories, art quality varies quite a bit, same can be said about the story quality, and while we're getting ton of good stuff, there might be a sea of mediocre/low quality content waiting beyond floodgates of the language barrier.