slight counterpoint my friend
debuting minors in kpop is purely an age and numbers game...especially for female idols
female kpop idols have an expiry date whether one wants it or not...how many GG actual renew (of the thousands of kpop GG less than 10 have had all members who debuted renewed with the same company they started with) how many are still active post 30? 35? 40s???? how many are relatively successful????
therefore being a female kpop idol - it means you only have a certain amount of time to build up fame, money, popularity before moving onto something else whether as a result of your own choice or having that choice made for you (early disbandment, fellow group member scandal etc etc) thus the earlier you debut the more opportunity you have to build up those things (fame, money, popularity)
For example if someone like Wonyoung debuted in a standard 7 year contract GG she'd be younger when she finished than the likes of Jisoo, Nayeon, Irene when they debuted
now I'm not naive enough to believe that debuting minors doesn't come with it's own issues such as their exploitation and sexualisation but those can happen to "adult" kpop idols as well but from a pure career and financial perspective it makes sense to debut earlier