Carr wanted to be traded prior to restructure per NOF and CBSsports
There was no world where Derek Carr took a paycut to be traded.
1) He has signed his last multi year starting QB contract. He wouldnt give that up. The next deal he gets will be a 1 year deal, either to be a bridge to a rookie QB (which is hopefully what he does here for 6 weeks) or maybe to become the new Vinny Testeverde/Joe Flacco where teams call you when the rest of their QB room is injured.
2) You cant trade what no one wants.