I will say this my friend
kpop groups (especially female ones) have an expiration date whether one wants to or not
in the entire history of kpop groups only 4 groups (Dreamcatcher, Mamamoo, Twice, Blackpink) have had all members who started sign with the company that they debuted with
there are many reasons why groups disband - different directions, getting older, scandals, starting a family, wanting to get out of the entertainment industry etc etc and therefore individually as a female kpop idol you only have a certain amount of time to perform as a kpop idol
and therefore the younger one debuts the more time to earn $$$ - count of the number of female kpop idols who are still in the business in their thirties or forties and then count how many of them are "successful"
WY debuted in izone at 13 (or was it 14) and if she had a standard 7 year contract then she would still be younger than the likes of jisoo/irene/nayeon when they debuted - that's an entire contract's worth of earnings