Why the Spurs would do this:

Brown would give San Antonio a legitimate second star to pair with Wembanyama, addressing their need for a primary scorer and playmaker. At 29, Brown's prime perfectly overlaps with Wembanyama's developmental arc, creating a win-now tandem for the next several seasons. While giving up three solid players in Vassell, Johnson, and Champagnie, plus draft picks, the Spurs would be consolidating their assets to acquire a player of Brown's caliber. This would improve their ceiling by replacing a collection of good players with one great one.

Why the Celtics do this:

Brown's supermax contract would significantly impact Boston's ability to retain their other role players. By trading him for multiple mid-tier contracts, they could reset their cap sheet and get under the second luxury tax apron. Receiving multiple players and future draft picks would provide the Celtics with flexibility. They could either develop these assets or use them in future trades. While Tatum is injured, the Celtics might decide to take a step back temporarily to build a deeper, more sustainable core around him for his eventual return. Replacing Brown with Vassell, Johnson, and Champagnie would give them several quality, win-now contributors. Vassell is a younger, rising player, while Johnson is a proven scorer.