That's why you have to be damn sure you want role players over a third star, because once you get up against the cap...that's it. From there on it's the MLE and trades. That's why the Lakers got Pau, and then Shannon Brown, and Ron Artest, Steve Blake, Matt Barnes, etc. If they flesh out their roster around Kobe, Lamar, and Bynum...there is no Pau. But since they got Pau and his Bird Rights, they have him and all of those other guys too.
If we get Nash, let him stay here for a few years, and STAT and Melo's salaries go from $18M a piece, to $21-22M a piece, that's an extra 6 to 7 million dollar's you don't have to spend. If you're over the cap, and remain over the cap because of annual increase, it doesn't matter who's money/contract comes off the books...you don't have money to spend. That means no Steph Curry, no anyone.
Or you can have CP3, Melo, and Amar'e, some MLE guys, drafted players, and vet min contracts.