During the 1-4, lost by 2 to the Browns, lost by 3 to the Giants, beat the Saints by 8, lost to the Cardinals by 10, and lost to the 49ers by 22.
Since firing Rhule, they lost to the Rams by 14, beat Tampa Bay by 21, lost to the Falcons by 3, lost to the Bengals by 21, beat the Falcons by 10, lost to the Ravens by 10, beat the Broncos by 13, and beat the Seahawks by 6.
Under Rhule, average score margin was -5 points (19-24).
Since Rhule, average score margin is 0 (21-21).
They also got rid of McCaffery, Mayfield, and some others.
The bottom line is that Carolina made a management decision after game 5 to get rid of a bunch of salary cap and go young with more draft picks. Rhule didn't agree with this and thus they parted ways. This has nothing to do with his ability as a coach, just a change in philosophy that he didn't agree with.
There is no parallel to draw here. Matt Rhule has proven that he is a really good head coach in a lot of places unlike Callahan, Pelini, Riley, and Frost. He's a SERIOUS upgrade over what we have had over the past 20 years.