Just think about that. You're already determining that you're moving on from this player at 6 years if not sooner, but you're spending your 1st round pick on them. That doesn't seem like the way to build a sustained contender.
Or another hypothetical: say the Bills pick Breece Hall or whoever, win a Super Bowl, and Breece Hall is so good that they're like "we probably wouldn't have won the SB without Breece Hall." You really think they're not going to pay the man? Or He's not going to be holding out for what he's worth?
And before you say "well then we'll just trade him for a bunch of picks." You really think someone else is going to trade a 1st round pick for a RB?