Tatum would need to take a massive jump for Boston to win the title next year. I mean he would basically have to play like he did in the Philly series all season long. High level shooting efficiency, active on the boards, solid passing, and good to great defense night in and night out. Not just small stretches here and there. That would elevate him into the top 5 player discussion, which is where he needs to be for Boston to have any sort of realistic shot at a title. And even if he does that, is Boston going to be better than Milwaukee, Miami, Brooklyn, or Philadelphia (assuming Doc can do what Brown couldn't). Not to mention a handful of teams in the West (LA, LA, Den, GS, HOU).
The sooner the board realizes Boston's title shot are very long odds, the better off the board with be. IMO, Boston just doesn't have a championship level squad next year as I believe that Tatum needs at least another season to really turn into the type of player he needs to be for Boston to really be a contender and by then I'm not sure the supporting cast will be good enough (Brown certainly is, but what about the rest of the roster).