Marquinhos was mainly played in the midfield the last two years. Only went back as a CB when Thiago Silva or Kimpembe is injured.
The guy who was injured a lot is Diallo. And Kouassi has actually all his chances against him. He hasn't impressed, always injured. Beautiful on the ball but disastrous defender. Another waste of 30 M+ by PSG with this guy.
And yeah, as you pointed out, Marquinhos is far from being a top CB. So, Kouassi opposition was no top CB at PSG. He has no excuse about competition or playing time at PSG, really, especially with a coach who likes him and trust him. How many 17 y.o. enjoyed this treatment at a big club ?
Year after year, i wish PSG would just stop their academy. I have rarely seen as many ungrateful young players than in our academy. 0 loyalty, nothing.
In this big business football, the academy is pretty much the only place you could still hope and feel there would still be some attachment to the club, the region, etc. However, even when they are given trust, it amounts to nothing.
On Koulibaly, i'm agreeing with all your points. I was even saying last year, amid de Ligt saga, that PSG was trrying hard for Koulibaly. The player prefers the PL though. Also, two years ago, he was an absolute monster. He nullified our attacks almost by himself. Nevertheless, this year he was as bad as Kimpembe. Dunno about his price, seems overpriced to me. Would rather we spend on proven, top midfielder instead.