The Spurs should want Collins more than most and they have more assets than anyone that would be competing, also. Sexton and Collins are actually exactly the types of players they should be targeting (a ballhandler that can turn the corner/break the paint and a PnR big that can get on the rim with aplomb, switch between 4 and 5, and also space the floor).
Castle’s size and desire to be a PG pairs well with Sexton’s holes, Wemby covers maybe more defensive issues than anyone ever. The amount of chaos that a Wemby ball-screen can unleash isn’t realized until they have a ballhandler that can blow by a sagging big but also has the nominal shooting efficiency to demand being guarded on the perimeter.