Well, they're not going to get any picks back if there is a buyout. He would be a free agent who could sign with any team.
I just don't see Koby being willing to buyout Drummond just so he could go sign with a team against whom we would be competing. If it ever got to the point where he got truly disruptive - which I think would be extremely unlikely -- I think Koby would be more likely to give him the JR treatment and pay him to sit home.
Appeasing blackmailers isn't a good long term strategy, especially when the blackmail could be repeated so easily by others.