..they started automatically counting themselves out of being able to resign their own free agents to reasonable deals and started looking to the 76ers as a model of rebuilding
or
....they realized their current veteran "leadership" was pillow soft, and therefore had no choice but to dump 'em before paying them again and treading water through years or even decades of future cap hell / franchise mediocrity, and instead take the path the best run teams in the league do -- building via the draft and asset collection (i.e. Spurs, Thunder, Bulls, Pacers, and.. themselves).
Meanwhile, they hoped and assumed their fan base, noted for it's basketball acumen, would get that this is the smartest and fastest path forward to championship basketball again, and therefore would not kick and scream about it like spoiled little children.