I'm not saying you should NEVER replace a head coach. Sometimes the message grows old and it's time to move on. Perhaps that is the case in Pitt, but as I said, who do you want to replace him? Don't just say fire everyone. That is what I find amusing.
The Packers hired Matt LaFleur in 2019. Matt LaFleur went to 2 straight NFC Championship games after McCarthy's Packers were 6-9-1 in 2018. Matt LaFleur has 56 wins in less than 5 years as head coach of the Pack.
If Matt LaFleur gets the Packers in the playoffs this year he will get coach of the year. A first year starting QB and the youngest team in the NFL.
If the Steelers can find a Matt LaFleur, then by all means move on from Tomlin. Brian Gutekunst has a lot to do with what goes on in Green Bay as well. Not sure Tomlin has a great GM in Omar Khan. We will see what happens.
This is why I asked who you want to replace Tomlin?