Only way the Spurs would entertain signing CP3 is if Parker retires and they move Aldridge or Paul takes less. Those things won't happen (small chance they move Aldridge), so the rumors you may see are more click bait. I'm sure Pop would love to have Paul and I'm sure Paul would enjoy playing for a franchise like the Spurs but the money doesn't make sense and Paul, as the NBAPA head, won't accept less than his full boat. This is more about enjoying some "what if" scenarios and Paul trying to leverage Jerry West and company to make some moves he approves of.
Because of their salary situation, I think the Spurs will concentrate on signing some of their own and perhaps signing a UFA on the cheap. No major changes are expected this offseason with the small exception of possibly moving LMA, but it's a very small chance. Simmons needs to be a priority, even more than Mills. They're also expected to bring over Adam Hanga to join the roster..... He's an athletic wing who is considered to be one of the best international defenders and a guy who can dribble penetrate.