probably because people got a taste of how terrible #3 was and wanted to go back to better times. i thought the first one was far and away the best. i would rank them as: Tobey 1 Garfield 1 Garfield 2/Tobey 2 (tie) Tobey 3
rewatch the scene. i'm pretty sure his first message (the one that says STAY) is because he was freaking out, thinking he was stuck in the middle of nowhere. he then realizes that "we brought ourselves here" (or something along those lines) and gives murph all the info (first coordinates, then the data from the black hole).