I think this is extremely possible, and I think CP wants to badly. The only thing he has left to accomplish is getting a ring. He wants it desperately, as would anyone as competitive as he is, and he's running out of time and options. The Clips have done OK and given themselves chances, but it just isn't going to happen there. The only other teams who really have a chance to win a ring are the Warriors and Cavs, who don't need him obviously, and maybe the Celtics. But they've got a young star in Thomas who would be pissed off immeasurably if they signed CP. And that isn't at all what they need to spend money on, clearly.
I don't think the Spurs are as far behind GS as people think. People say they walked through the west 12-0, but they were down 25 at home to the Spurs before Kawhi went down. That is a big deal. Honestly, I think the Warriors were the better team and probably would have won the series, but you can't ignore being down 25 at home before the Spurs' star went down, and one of its PG's was out. Re: TP, he still has it when healthy, but at age 35+, health isn't a given and especially at the end of the year, even with managing minutes during the regular season. The Spurs need an PG badly, and he is exactly what Aldridge needs to be most effective: a true elite PG table setter, dime dropper, pick and roller. Mills nor TP are close to that. Would love Mills backing up CP, but good backup PG's are a dime a dozen. Mills is going to get offered big money, but he may end up elsewhere and try to prove he can be the man. And I wouldn't begrudge him that. But while he can probably be very good, he is not the PG you are going to win a ring with. CP, Kawhi and LM is a formidable core, and one that can be built around with any number of combinations. I think CP will take a pretty incredible pay cut to play with what is really the only team that gives him a chance for a ring. I suspect Pau would like to stay for that, but he is sort of the X factor. I don't see how he stays and CP comes. That is really the big sticking point, but maybe it can be worked out. I think the Spurs want it and CP REALLY wants it.