Why companies don't debut solo artists?

There are lots of popular solo artists in Korea too, they just aren't kpop idols. Kpop builds on attracting die-hard fandoms and I suppose groups are better at that

bc they barley do well

The scheme of having a group then multiple soloist out of it is more profitable

groups get a fandom easier which means money in kpop

part of the attraction for kpop groups is the members interactions with each other and it's hard to do that as a soloist