If you are facing a reality without Westbrook on your team any way, why not go to a team that has Horford on it...and who knows, a year from now, maybe LA won't look as appealing to Westbrook, and he gives serious thought of rejoining KD on the Celtics.
That's the way I would look at it...come to the Celtics, make this YOUR team and draw others to you.
It's legacy time...no better city/fans than Boston!
Rak