Most of the top TE's from this past generation weren't 1st's obviously (Gronk, Witten, Gates, Kelce, Kittle), but Gonzalez was, the seeming heirs to the throne (Hockenson and Fant) were, and even some of the guys who were supposed busts (Vernon Davis, Eric Ebron) were actually Pro Bowlers who were among the league's best for short periods.
But is it really uncommon to have a bunch of top players from outside of the 1st?
The majority of the best OG's over the last 20 or so years (Will Shields, Larry Allen, Marshal Yanda, Jahri Evans) weren't 1st rounders, does that mean we should pass on Zack Martin in the first if he's projected to move inside? How about Rashawn Slater?
I'm sure it's similar for other positions.
The real crux of the Pitts argument is that the guy is arguably a prospect that we've never seen the likes of. If you extrapolate his 8 game stats over a standard 13 he would've put up 1200 yards and 19 TD's. Those are WR stats, or even better in terms of being a red zone threat, and that production is something guys like Hockenson or Fant or whatever other modern highly ranked TE would've needed 2-3 years to replicate.
Outside of Lawrence it's damn near a consensus now that he's probably the cleanest evaluation in terms of translating to the NFL at an elite level, that isn't something we normally hear out of TE's going in the first. He's rare, otherwise nobody here would even want to consider him given our defensive needs.