To my surprise we haven't played 352 but Dumfries plays very high on the pitch, which is why de Vry kinda plays as a RCB that also covers for the RB. De Vrij is more comfortable in this than de Ligt.
I think that's the main argument.
I feel like de Ligt is an 7/8 in nearly every aspect, aerially, strength, agression, ball playing, covering zonal area's, composure, goalscoring, rushes, speed.
But then you will have someone like van de Ven, who looks like the fastest defender on the planet which is a huge weapon. Or Ake who's super athletic, agile and smooth on the ball. Timber who's extremely fast, agile, and a great dribbler who can take the ball forward.
Not to mention Geertruida, Botman and later the likes of Hato/Beukema/Schuurs/Teze who can really develop. When de Vrij and van Dijk are too old, there will still be so many great options.