Because Koreans are the main market for manhwas and Korean men dig those harem + OP MC stories no matter how shitty and copy-pasted they are. It's also why BL and RoFan rarely get axed-- because Korean women will probably pay their entire monthly salary to keep it going.
Manhwas like this are for the general audience, and that would mean the risk is higher for them because nobody would stubbornly keep buying it unless they genuinely love the story.
A lot of Korean artists/Korean authors probably want to create smth different too but are too scared to risk it or are told by those managing them that it's not worth it, so all they could do is create a copy paste of a typical power up story so they could earn some cash so they.
It's sad af but it's the reality.
Why do good manhwas with great story like this one get cancelled,but the ones with brain rot writing and unrealistically proportioned females that blush and salivate after the mc at every turn get like 3000 chapters? (╯°Д °)╯╧╧