Mobley was not going to sign here, and that's the bottom line. He was offered more to get traded by the Kings, but he chose to sign with the Clips because he wanted to be in LA. Petrie tried very hard to get something done with him, but ultimately he couldn't stop Cuttino from doing what he wanted to do.
Jackson was not trade for the bench, he was trade for Bonzi Wells. This was the right move- Wells right now is contributing much more than Tag and Jackson would.
House and Songaila walked because Petrie thought that money could be spent better elsewhere. That money turned into Shareef, luck or not on Petrie's part. Had they been resigned we would look like this:
Bibby/House
Wells
Peja
Thomas/Songaila
Miller
Not much of an improvement, IMO. Maybe Kenny would have continued to play well without SAR, but he might just as well have fallen flat again, as he probably didn't like Darius encroaching on his minutes and got out of his "I just broke out of Philly" mode.
There was really no winning hand this offseason. Petrie can't just trade for Kevin Garnett. Believe it or not, reality constrains what can and cannot be done. Players and GMs have their own desires and look out for their own bottom lines. This offseason worked out as well as it possibly could. Hart was a solid pickup, Thomas was supposed to play well of the bench, and Garcia was praised as a steal in the draft. The future is unpredictable. At the time, Geoff did everything as well as he could. This failure is out of his hands. Blame should lie with the players and the coaching staff.
Now, I think it may be time for a change at GM anyways. Petrie is still offense-first, and his unwillingness (perceived) to trade Peja for Artest is baffling. If that offer is available and he balks at it, then we have something to talk about.