If you believe that Petrie wanted to fire Adelman, then you know nothing of his past history. Petrie walked away from his job in Portland because they fired Adelman against his wishes. They are close friends, and though some can nit pic some of Adelman's decisions, such as starting Webber after the injury, there was really no reason to fire the man. The Maloof's made no secret of the fact that they didn't get along with Adelman. It was their decision, plain and simple.
Yes Petrie is paid to take the heat for the organization. Thats whether he actually makes the decision or not. But there is a difference between taking the heat and actually being the one responsible. The Maloof's have been able to hide behind Petrie until this year. He's in the last year of his contract. They offered him a multiyear extension and he turned it down for the present.
This is just my opinion, but I believe this was a statement by Petrie to the Maloof's to let me run this team my way, or I'm out of here.
I believe that Petrie is the longest tenured GM in the league. He wouldn't have a problem getting a job somewhere else if he wanted to leave. He's not perfect by any means, but he's certainly one of the better GM's in the league. His main problem is that he's just not as sexy as some of the others, and he doesn't create any news for those of us just sitting here waiting for any rumor to feast on.