That's fair. But again, I don't think you should expect to keep every first rounder, may be not even most first rounders, past their rookie contracts. There's just not enough money to pay everyone. There's definitely a trade off from the known commodity to the unknown. I think at that point you have to look at the teams needs vs the player (or rather the cost of replacing such a player).
Such as, if you have a decent replacement for Conk on the roster already (which we did in Kelly) and can draft a OT early, maybe the 15 million you were going to spend on Conk would be better spent improving your pass rush. Unfortunately, the plan unraveled from there, but it's pretty hard to predict player's not having motivation (Beasley/WIlson) or injuries (Clowney).