They actually did that until Burke was just so bad a change had to be made. And I think it was more for Hayward's benefit, TBH. Trey was taking too many shots and Gordon was pretty invisible in the 1st quarter especially.
As One Love said, Jazz are ready to win NOW! All the other starters are ahead of Exum in terms of skill level. How many minutes did Stockton get his first 3 years? 18, 24 and 23. Learning behind a former all-star (Green) certainly didn't hurt John's career. I think Dante could even learn from Neto. Make Exum EARN his spot through his play. Last season he was horrible offensively, Do we want to risk another season - and possibly Hayward - on the basis of one summer league game? What if the injury has made him timid again? What if he's not able to improve his shooting? Then the Jazz maybe win 46-48 games, are a lower seed in the playoffs, lose in the 1st round and Hayward decides to go to a contender.