I like him, but not 75 million euros like him. In the end just look around Serie A.
Bastoni, Skriniar, Koulibaly, Tomori, De Vrij, Kalulu, our past/present CBs Benatia, Barzagli, Chiellini, Bonucci was not close to 75 million euros. It comes down to scouting, you can find great CBs for good prices.
If someone where do offer 75 million euros + for De Ligt I would let him go. Get one great CB like Koulibaly if possible or hijack the Bremer deal. Then get one cheaper.
De Ligt is great and can become better, but so far has he lived up to the hype? A generational talent costing a fortune? No I don't think so.