Different JR and you know it
Fox wasn't fired cause he didn't want to pay him out. Hurney wasn't even under contract
I think that was a factor, but this was a convoluted decision and I think you are over simplifying it.
Keep in mind these factors. Yes John Fox went 7-9 in 2009 but he also won the NFC South in 2008. John Fox expected an extension after going 7-9 and didn't get one, couple that with them releasing Jake and some other veterans that were Fox favorites, and suddenly Fox got his ass on his shoulders.
No one really saw 2010 coming. Despite cutting some veterans a lot of people were excited that Matt Moore was now QB instead of Jake because of Moore's strong showing at the end of 2009, the rest of the offense was mostly intact (at least at the skill positions) going into 2010. Many people thought we got a steal in Jimmy Clausen in the 2nd round. And most people thought the only thing holding us back was our QB play.
Here is what Pat Y had to say about us in the ESPN preview to that season:
DIVISION FINISH: 3 Don't dismiss Carolina. National expectations might not be high, but I don't see how a team with core players such as Steve Smith, Jordan Gross, DeAngelo Williams, Jonathan Stewart, Jeff Otah, Ryan Kalil, Jon Beason and Chris Gamble can be terrible.
But Fox was angry he didn't get his extension after a disappointing 2009 season and decided to cash his $6 million dollar paycheck and phone it in the 2010 season. Not to mention Moore got hurt and Clausen ended up being pretty terrible.
JR also didn't extend Fox partly because he challenged him to be a more consistent winner. He didn't want to extend Fox, thus committing additional years worth of salaries, without Fox having consistent winning seasons. I realize this runs contrary to the "JR doesn't care about winning he just wants to save money" narrative. I think it was a message of just the opposite.
And of course the lockout played a factor as well.
So all those different scenarios are the reason he wasn't fired, in addition to your belief that he didn't want to pay $11 million to a coaching staff that wasn't even working for him anymore. which I agree was almost certainly a factor as well
But I think it is a little bit unfair to say that JR didn't fire the coach that had just won the NFC South the season prior solely for financial reasons.