If they like the player but feel his value is only at 20 or 24 or 36, they're going to trade down. That's all there is to it. BB isn't going to over-pay. He's never done that with a 1st round pick. A lock-down corner who you control for 7 years (5+2) such as Gonzalez or Witherspoon is worth as much as that starting tackle.
If someone makes them an offer to trade back from 14 and they think the guys they want will still be there, they'll trade back.
You have no idea what the Patriots will be relying on in regards to the tackles. None at all. Just like I don't. For all we know, Brown is shifting back to RT, Strange is kicking out to LT and the Pats will be focused on drafting Darnell Wright in the 2nd round. OR Brown could stay at LT with an open competition between Reiff, McDermott, Anderson, Cajuste and Stueber for the starting RT position with Washington learning behind Brown. You sitting there and saying anything with certainty like "We' be relying on Reilly Reiff" is just silly and shows a very limited understanding of who we have on the roster at this point.
Again, you claimed "common sense", but there was nothing you offered that fell into that category.