Not an "Olineman", sweetpea, an All Pro left tackle. Next to the QB, the most important guy on the offense, and good ones are hard to find, so you pay him. Good OT play is so important to making the entire offense, both pass and run, go that you can't just let a good one walk. You don't realize how much you need that big ugly on the left side until you don't have him in there.
The chances of Miami getting another LT as good as Long and in his prime are slim and none. Yes, the Fins might get a couple of firsts for him and they might have another decent LT in Jon Martin, but an All Pro LT in hand is worth more than 2 or 3 might-bes, which is all that draft picks are.
Furthermore, as I always ask some of my fellow Bills fans who seem to always want to trade good/great established players for draft picks, why do you hate your team so much that all you want to do is help help other teams with the guys the your own team developed? F the Bears (or whatever team). Let them find and develop their own LT.