I think defensive dmen should have an adjusted timeline than say wingers. but I get that the big club is literally dying for the services of a guy with his profile.
I mean obviously every case is going to be different, but regardless of position I can't think of many guys over the past decade or so taken in the top half of the first round who spent more than two seasons in the NCAA. That seems to overwhelmingly be the development path for players in which teams are investing top picks. I'd imagine it's at least in part because if a team is spending a top pick on a player, they think they're basically pretty close already and they expect that player to be ready to move into a pro schedule sooner than later.
Edit: I looked and going back to 2010, unless I missed someone (which is entirely possible as I didn't look super hard), it's just Derek Forbort (15OA 2010) and I guess Matthew Wood (15OA 2023 - if you count him, since he played his first NCAA season his draft year and is still there now in his D+2).