Again, there's zero reason why Boston would trade for Kawhi. They have Hayward locked in for three more years and two players they really liked on rookie deals. If Gordon were healthy and just not clicking, maybe. But they are almost certainly more inclined to see what they already have than make any substantial change at the wing. By far, the best thing PATFO can do is wait until the draft and pick their own guy. LAC has two picks in the lottery this season. Neither is great, but that doesn't matter if they guys PATFO want fall to them. I have no idea at all whom that would be (don't even have DX anymore to check prospects out), but if someone they think can be a really good player is there, those picks plus Harris for Kawhi and Patty and/or Pau could easily outclass a Boston deal. There are others too, like a deal with Phoenix (who could have two lottery picks themselves including the a top-three pick).
The Spurs could have a young group with Murray and the haul from the deal with the potential additions of guys like Anderson, Bertans and Milutinov. They'd also still have a vet core of Parker, Green and Aldridge to keep the team watchable. Finally, they'd have no bad salary on their books going forward and a legit chance to FINALLY fix their weaknesses at the guard spots. That feels like a much better prognosis than trading for Boston's guys and then hoping to be bad enough to get a real star in the lottery. People don't even want to watch the team when they are firmly in the playoff race. They damned sure aren't going to watch a tanking Spurs team, despite what all the people who are pushing for a completely bottom-out seem to think.