They should have done the Kawhi Leonard trade that summer. Just pulled the trigger and included Brown. Boston wins the title that year and who knows maybe Kawhi and Kyrie stay and that is the start of a dynasty.
Have you watched the last couple of years of basketball? Why not trade for Zion, Ben Simmons, and Klay Thompson?
I'm not sure what that post has to do with mine. Kawhi was actually traded that summer and Boston was the rumored front runner, but didn't want to part with Brown. I would have done that trade at the time (as I said pretty consistently on here). Given Toronto went on to win the championship that year and Boston hasn't won one yet, I think that was the right move to make and still do. Even if Kawhi and Kyrie both left after that year, Boston almost assuredly would have had another banner hanging.
The Spurs basically wanted Brown and draft picks, though Smart in a sign and trade could have also been included. Assuming it was Brown and Smart (and a future pick), that would have left Boston to start that year with Kyrie, Kawhi, Tatum, Horford, Morris, Rozier, Hayward, Baynes, Theis, Semi, Wanamaker, and Rob (the latter 2 were rookies). That team is pretty clearly and significantly better than the Toronto team that won the title. And I'm not so sure they both would have left had Boston won the title especially because I don't think a lot of the in-fighting would have happened with a much clearer hierarchy with Kawhi at the top.