First, there is always a problem when a family member like this uncle gets involved. (Ref: LA and Ball) If the family tie is really tight, then a young player is likely to listen. There isn't anything the FO can do to make SA a popular destination for prime free agents. LMA is the closest the Spurs have ever come and he had a lot of Texas ties. And we don't have any really good trade bait to bring in another really good player to complement Kwahi and LMA.
So we may be in for some very lean years like most teams go through. The wonder of the Spurs is our 50+ win streak that will probably never be broken.