TBH, I'm a bit surprised that the Celtics are interested in getting Durant to the point that they will trade their core players just to get him. They reached the NBA Finals without him so what's the point in getting him? They only lost to Warriors because of experience that's all but I believe this current core players of the Celtics will get a championship in the future. That's how promising these players are.
The point is they still lost. And if the management gets some hint that they could improve their roster to guarantee a championship, they should explore it. I too, do not agree that they should break their core for Durant, but I am not an expert. And their GM is doing fine building this team so far, maybe we could give him the benefit of the doubt and trust that he could still make this team better than it already is. 
.Well, if Brad Stevens' decision if he will keep the core players intact or he will make some exploration and trade one of them to get one of the greatest shooters in the current era (maybe we can add one of the few players out there who has more authority than the owners). After all like you said, the GM knows what is better for the team so let's just wait for their decision. Well aside from the Celtics, the Sixers are being included in the conversations as well.
Speaking of the Celtics… After the passing of Celtics legend Bill Russell the NBA has said that no player for any team will ever be given the number 6 ever again. That makes Bill Russell the first NBA player to have his number retired league wide. A pretty huge deal as there are only so many numbers. I’m sure the entire season will be filled with tributes to Bill who was a championship machine when he played.
Well deserve.He has been a very influential person inside and outside the NBA. 11 championship rings and for sure no NBA player will ever do that again and he did that in 13 years only. All of the players will have a patch to their right shoulder to honor him and each homecourt will have a clover shape logo with #6 on it in front of the scorers table. The #6 jersey will be retired worldwide but players who are currently using #6 jersey will still be allowed to use it so players LBJ, Porzingis and others can still use it if they want to.