Tbf Nino, comparing s Kpop artist to someone having writers isn't really fair. This video for example is a good example of what @Joannesrats means. I'm not saying this is what happens with all Kpop artists but this was only a few years back and was aired on the BBC. It's a documentary of my favorite Kpop group but in one scene they showed what the selection process it. It's also mentioned in the documentary that these Kpop stars aren't even required to be good singers. I imagine this is common practice in the Korean music industry. It's timestamped.