Saying there are no good games on mobile is just ridiculous. Not just because quite a few decent PC games were closely ported to mobile, usually without predatory bullshit. But everything with a price sticker has to compete with "free". Saying the market will sort things out in favor of good games is just as ridiculous. Predatory tactics seem to work quite effectively, seem to make money for the industry and as such wont disappear anytime soon. Maybe if they go overboard and we consequently get some decent regulation.
There are a number of good reasons PC gaming is still a lot different from mobile, like how it started in a widely different position and still has quite different target audiences. But there is no indication it will stay that way, at least in terms of awful business practices.
No, they can only do this because there's actually a solid market for what I (and I assume you) see as awful games for extremely portable handheld devices; essentially, I think they are pretty much digital fidget spinners.
They can only do this in the absence of competition from non-awful games. You claim that those games exist, but you don't support that claim in any way. Why do you think they haven't displaced the awful games?
There's an infinite number of terrible games being constantly turned out for the PC too; the difference is that the PC also has good games.