I'm not sure if Dallas does this. They lose their chance at a top pick in a loaded draft for a couple guys who can MAYBE help them sniff the playoffs this year - it would take a serious comeback, even if the trade happened this moment - and how does it secure their future? Does Dirk have more than this season left? OK, he might last one more year. Then what? You're left with Gay, a 30-year-old IT, and a couple decent young guys in WCS and Barnes, no 2017 lottery pick.
I dunno. Not sure Mark Cuban would take such a risk for something like this unless he was confident he would get a surefire playoffs run for Dirk out of it.
Plus, Sacramento is clinging to the 8 spot in the west. I doubt they move Boogie - though knowing how desperate and idiotic their ownership is, maybe the illogical is to be expected.