This is the D.A.'s call, not Apple's. From the D.A.'s perspective, a crime was committed and now wants to pursue. Don't see how Apple is pulling the strings on this.
Well, let me ask you this: You lose your phone. The person who finds it contacts you and you don't reply for weeks. Then you contact them finally, and they say they sold it because you showed no interest in it. They give you the contact information for the person who bought it off them from Ebay. You contact the 2nd person, and the 2nd person IMMEDIATELY offers to give it back to you. You meet them and they return it as promised.
Now, do you honestly think you can call the cops, and they'll go and break down the door (LITERALLY) of that 2nd person, then take every electronic gadget they have for 'evidence'? I don't think so, and I doubt you do either. Clearly the cops are doing things differently because Apple's involved rather than an ordinary citizen.