I actually disagree that Westbrook isn't worth trading for—that he's merely "an empty stats kind of player" (though I do think he's been somewhat overrated the past few years)—but I agree it's hard to envision much of a market for him, one that would make it worth OKC's while to trade him. Who out there really has the combination of assets and needs to really pursue him?
Boston would have been an interesting option before acquiring Irving. But OKC, while perhaps too proactive in trading Harden, maybe should have been a bit more proactive in moving Westbrook once Durant left; exploring something with Boston last off-season would have qualified as proactivity.
San Antonio would be an interesting dark-horse if Popovich keeps coaching, they can resign LMA, and they decide they want to cash-in for one final window (hoping for the best with respect to Leonard's ever recovering). But I don't know enough about their assets, cap-space, et cetera, to judge if it's viable—plus it doesn't seem like the kind of move their FO would find "prudent". And yet, I think Popovich is the kind of coach who could maybe channel Westbrook's best abilities and curb his worst proclivities.
Maybe the bumbling Bulls FO would be desperate enough to accelerate their rebuild (and keep their jobs a little longer) to consider Westbrook. But I'd be surprised if they'd be willing to give up this year's higher first (#6 pre-lottery), and I'd likewise be surprised if OKC would accept anything less as the key to the package.
It's just a tough time to be rebuilding in general, with teams hoarding picks as they are—Cleveland wouldn't even trade Brooklyn's first to placate LeBron at the deadline. Though who knows: maybe they'd work as an option if they were willing to let that pick (plus other assets) go and pair LeBron and Westbrook (contingent on James' re-signing, obviously).
