I'm not a fan of monopolies, and duopolies are hardly much better. Healthy consumer landscapes typically incorporate a wide gamut of independent platforms and choice, with a carefully curated but limited amount of exclusivity between them. (Which is where streaming went bad. Too much exclusivity.)
Between Kakao and Amazon, the latter of which has a reputation for treating its workers as less-than-human, I'm not liking the landscape that's unfolding before us. We've seen it from Google, with how YouTube creators have to bend themselves into pretzels to appease algorithms and avoid demonetisation. There's no other large platform for them to flee to. Watching the tides of such change encroach further into niches I thought had a decade or so more of independence is... distressing.
It's not going to turn me off online publishing. I can tell that this is the way the winds are blowing, and I'll grudgingly work with whatever platform I have to in order to make a living and share my work with readers. But I don't like the shape it's taking. Like an extra limb grafted onto the monster of late-stage capitalism.
EDIT
The one thing we as creators should be pushing hard for is the right to publish and monetise on multiple platforms, unless the platform itself is paying us to create content. I'd be fine with having a series exclusive to WEBTOON, for instance, as they pay their ORIGINALS creators an actual wage for every episode. But this trend of "You can monetise on our platform, but ONLY with us" is worrying, especially when they're subscriber-based platforms.
As a parallel example; many people can't afford to subscribe to multiple streaming services. The same will end up true for serialised fiction on subscription-based services. Creators will lose out on potential audience and revenue due to the splintering of readership between two or three large, exclusive platforms.
Hell, even with free services, you'll find people completely ignoring one because they simply prefer the other. Many webcomic artists post to both Tapas and WEBTOON for that reason. The freedom to monetise on multiple platforms, unless we're being paid a contracted per-week or per-episode wage as licensed creators by a platform, is a right we creators should be loudly demanding.