Just based on reports, I think he was low-key shopped at the deadline. I'm guessing that no team offered enough to make it worth their while. I'd be shocked if Danny Ainge hadn't called. He's the most available superstar right now. Davis might be soon.
Here's the thing: are we sure he's that good? I mean, I know this is heresy, but it's a legit question. Obviously he is a great defender. I think any team would be better with him defensively.
But offensively, are we sure he is that good? I know he is good, but is he an offensive superstar? He averaged 26 points a game one year in his career. That was the first year that he drew fouls at a high rate (over .4 FTR). He is not a great passer or ball-handler.
He dribbles a lot. He holds the ball a lot. He is not great at ball movement (which could be the product of the offense, or it could be Pop creating an offense around Leonard).
On top of that, he has been injury-prone in his career. You can't really play him at the 4 because you risk his getting injured with the physicality (a dirty secret is that the reason Pop moved to a two-big lineup with Leonard at the 3 is because he wanted to protect Leonard).
Let's just say that Leonard's success is, at least partiallly, due to the system. Let's say that in a normal NBA system as the first option, he would be a 20/5/2 player with elite defense.
Are we sure Brown isn't going to be that in two years? Is it worth trading Brown, plus depth, plus picks for that if Leonard isn't a significant upgrade in the long run? Some team looking to make some noise will trade for Leonard, but I'm not sure we should.
The team I wonder about is the Lakers. Isn't Leonard a California kid? The Lakers could give Ingram for Leonard (they will have cap space to absorb his contract) and then sign Lebron James. That would give the Spurs more youth and a valuable trade exception.