Well it was the plan the entire time to have the Spurs dominate the finals, the other scripts were diversions
The reason the NBA wanted a Spurs dominant victory was to get LeBron pissed, and have him work extra hard in the offseason and go on a redemption tour in 2014-2015. LeBron's 2014-2015 season will be the greatest single season in NBA history for a player, and he just needed a humbling loss in the Finals to give him that extra edge to go into the next season to dominate. LeBron will go bonkers all season next year, motivated by the embarassment and will make up for it and more.
This Spurs win was scripted to fuel the LeBron revenge tour in 2014-2015. It helps set up the narrative and storyline the NBA wants. It will drive up regular season ratings.