I'm pretty sure they traded for him knowing he was expiring. And quite frankly, the Lakers don't play by the same rules as the rest of the league anyway. We were stupid for not trading Aldridge before he was unrestricted.
It was a perfectly reasonable decision to not trade Aldridge. The CBA was setup back then in a way that more heavily discourage players from signing an extension, Aldridge would've given up a huge figure maybe as high as $50 million by signing an extension instead of waiting some months to resign the following summer. There were basically no franchise players in the NBA signing extensions at that time after their rookie extension. The Blazers had a strong starting 5 as obviously evident with the teams wins prior to Wes injury. The Lakers had Dwight walk for nothing, they took a risk, it didn't work once another time with Davis it did. Toronto lost Kawhi but the Thunder resigned George. There is a risk with this, if a team tries to avoid 100% of risks the team will never win anything. Go hide in your bunker and keep your money under your mattress if you are so scared of every risk. I'm glad the Blazers took some risk and tried to win in 2014, instead of being safe, getting a draft pick, and accept a few years of losing. Sucks it didn't turn out better, but teams will never have perfect predictions on this stuff.
The Thunder traded for George on an expiring deal, with the idea that they were trying to convince him to stay. Same with the Lakers and Davis. That's completely different. And yes, if Nurk is unwilling to sign an extension before becoming unrestricted we should definitely trade him.