Nobody is going to give up more than the Lakers, when Leonard isn't guaranteeing he'll re-sign, in fact he's even implying he won't re-sign and plans to sign with Lakers in off season. Kawhi also was cleared by the Spurs last year and just decided he wasn't going to play because he didn't trust the Spurs, or whatever his ******** he was spewing was. When you have a guy, who literally will quit on your team and not play in playoff games, he's demanding a trade, and won't guarantee he'll re-sign with anyone but one team, its hard to get much value for him and other teams know this and are either avoiding the situation or low balling. There is no reason for a team like, say the Celtics to give up Brown or Tatum.
Ingram is only 20, and improved a lot last year, he definitely has trade value, and there is no way to possibly know how good or not good he'll end up being, but he's definitely improving. There is conflicting reports of what LA is actually offering, but its hard to believe San Antonio get's a much better offer than Ingram and Kuzma, two good young players.