I would like to say that I'm not trying to insult or argue with you. Though, I may be bad at explaining things in English.
I don't know what defines a good work. It's subjective no matter what we do. However, we can still judge a part of said work. We can say that we like\think this work is good, yet we as well can say that a particular part of this work is bad. For example a game. We can say that gameplay is addictive while the story is garbage. The design and music are ok and in the end, we judge the game to be great. Why? Because for said person gameplay is more important. Yet he doesn't deny that the story is bad. The other thing that I want to add, is manga\webtoons are a combination of art and story. The story may be good, but if the art is terrible it will lose to a more mediocre one. The one that has both parts somewhere in between the good and bad. We shouldn't dismiss the good art. And I've not seen anyone who said the art in Solo Leveling is bad. However, this is a complex thing. It's a combination of art and story. And if you dismiss that the story part sucks, then you can just enjoy paintings instead of the manhwa. If a complex thing gets attention because of a single feature it doesn't negate all the things it sucks at.
For me Solo Leveling is hollow. I've read maybe twenty chapters before I got bored and dropped it. Yeah, the art is great, it was the thing that made me read it in the first place. However, when I've got my share of great art what were the things that I was left with?
I disagree with the point that good things wouldn't have a low reader base. I think there are a lot of different examples of how good works were overshadowed by those more popular. I can give you examples if you want.
"I agree, it would suck if making a story popular boiled down to just having good art, because it would bury people who don't have access to that kind of thing." In the end, this is how I see Solo Leveling. It's a hollow webtoon\manhwa, that overshadows everything because of the great art. It doesn't mean I'm right with how I see things. But I involuntarily connect this with good works being axed.