I've expounded on this before but dating back to their acquisition of Kendrick Perkins, nearly every big move Presti has made has been a disaster.
The Perkins trade, the Perkins contract extension, being unwilling to go from 10 mil to 12 mil per year in Harden's contract offer, trading Harden for beans, not using their amnesty when they had Perkins massive dead weight on a contending team, trading for Carmelo, trading Carmelo away and taking on a ton of salary instead of just waiving him, the panic attack Westbrook trade.
Presti landed some all-world talent via some trade fortune... he proceeded to piddle it away, never building a complimentary roster, then lost all 3 of his superstars for virtually 0 return. They now have one of the older rosters in the league, they're a luxury tax payer and they're contending for nothing.