RFAs are fool's gold. If it's a good player, the other team will always match.
Then again, this is legendarily cheap OKC we're talking about, so I guess Jackson is more attainable than Butler/Leonard.
Jackson is exactly the kind of almost-star that might be willing to come to a rebuilding team as well. Young, improving, sick of playing second-fiddle and looking for someplace where he can be alpha dog.