Obviously the NBA is a business and players are well-paid adults who understand that being traded is part of that business.
Still, as the OP points out, another part of that business is being able to attract talent to your city and franchise. Boston is not LA, where the weather and celebrity culture along with the winning tradition sells itself. What's made the Celtics attractive in recent years is the success of the team on the floor and Doc Rivers' presence as coach. Insofar as what the players like about Doc is his belief in ubuntu and family and loyalty, I think the Celtics would be wise to protect this part of the brand going forward, perhaps more than Danny Ainge and some of the armchair GM's would like. The loyalty doesn't have to blind, i.e. they don't have to say, "we are never trading" a given player. But I do think loyalty should be taken into some consideration, in the sense that the team shouldn't be so eager to flip guys like Bass, Green, and Lee after they just signed. Those guys wanted to be here. That's worth something today, and showing some loyalty to those guys will be worth something to the franchise in the future.