It's important to state right off the bat that DeMar DeRozan is an incredible athlete. He's one of the best players to ever put on jersey for any squad. And his run in Toronto should be enough to get him a Hall of Fame berth.
That being said, his prime years are most certainly behind him and retirement is closing in. It's quite likely that his time on the Sacramento Kings will be his las NBA run.
For some reason, the NBA as a whole doesn't seem to want to acknowledge that. But the league's response to Sacramento's trade overtures pretty much says everything.