If the Spurs were to give Paul a big contact, which I would think it would be a disaster in 3 years time, the spurs would need Gasol not to pick up his option, Manu retire, renounce Mills, and trade parker for naught, and give up on Dedmon, Simmons, Lee, and possible Gasol if he does not sign for a min.
Other words, Spurs trade Mills, Parker, Manu, Dedmon, Simmons, Lee, and possibly Gasol for Paul and bunch of minimal contract.
However if Paul wanted to take a 16 mil contact, then it would look different.
TLDR, it won't happen.