My guess is that after the second game the Spurs team sensed that the Suns were starting to crack emotionally. They were probably reminded to stay calm, don't actually fight, and STAY ON THE BENCH. Then it was just a matter of pushing the envelope with hard and/or dirty fouls until the Suns over-reacted and got some of their people suspended.
The Spurs' experience and poise may have paid off for them.
Maybe so, or maybe Tim Duncan and Bruce Bowen leaving their own bench in the 2nd quarter following some hostility between Elson and whichever Sun it was will cause Game 5 to be a pulsating matchup between Burke and the nameless Argentine guy.
Rules are rules.