3 reasons :
1. Sacramento is 16th in home attendance in a new arena. That shyt will plummet so fast when you don't have much of anything to move forward with (all their rookies are either raw as fukk or are underachievers). Think about it from a PR standpoint: "Come see Malachi Richardson and the Sacramento Kings!!!" "Witness Georgios Papagiannis and the Sacramento Kings as they take on the Golden State Warriors!!" Go to the Kings store with nothing but Skal Labissiere jerseys

When you transition from one guy to the next, you do want at least a place holder. Every team has one. The ones that don't are assured to have empty seats. They don't wanna take that L even if it makes basketball sense.
2. They wanna trade Gay and Cauley-Stein first.
3. They want a King's ransom for him (pardon the pun). A pu pu platter of picks doesn't appeal to these teams anymore. Ainge is struggling to comprehend that. If the Celtics are in position to select say a Fultz or whoever, the Kings might entertain it, but then Boston's gonna get cold feet. If the best thing you have to offer me as a prospect is wack ass Jaylen Brown, then go away.
EDIT: One more reason: they're not THAT far from 8th seed. 2 games out , 1 in the loss column. 10 years out of the playoffs, if you can get in even as human lube for Golden State, that boosts morale for a team like the Kings