Why do you keep citing coaches that died or retired before the salary and attempt to prove you're smart and I'm stupid?
Not one of those coaches died before the salary cap started. Well, my dad always said Landry looked like a walking corpse on the sideline, but I think that doesn't count. Landry's official death, the earliest from all the guys listed, was in 2000, after six seasons of the salary-cap era had been played.
In response to your newest version of your original incorrect assertion, let's take out the head coaches who either ended their long tenures before the salary cap or had most of their long tenures before the salary cap and very little after. Coaches eliminated by that last part are Levy, who spent just four of his 12 seasons as Bills head coach in the salary-cap era, Shula, who had just three seasons in the salary-cap era, and Fontes, who also had three.
That leaves...
Belichick: in his 24th season as Patriots HC, all 24 well into the salary-cap era
Reid: in his 11th Season as Chiefs HC, after having spent 14 seasons, all in the salary-cap era, as Eagles HC
Harbaugh: in his 16th season as Ravens HC, all of those years in the salary-cap era
Tomlin: in his 17th season as Stealers HC, all of those years in the salary-cap era
Carroll: in his 14th season as Seahawks HC, all of them well into the salary-cap era
Lewis: 16 seasons as Bengals HC, all of them well into the salary-cap era
Shanahan: 14 seasons as Broncos HC, all of them in the salary-cap era
Del Rio: nine seasons as Jaguars HC, all of them well into the salary-cap era
Payton: 16 seasons as Saints HC, all of them well into the salary-cap era
Fisher: 17 seasons as Oilers/Titan HC, exactly coinciding with the first 17 years of the salary-cap era
Cowher: 15 seasons as Stealers HC, two of them before the salary-cap era and 13 in the salary-cap era. This makes him the opposite of Levy, Shula, and Fontes. The same logic that removes them keeps Cowher.
Coughlin: 12 seasons as Giants HC, all of them well into the salary-cap era
I had previously forgotten Coughlin. I'm sure I'm forgetting others too. These are just the ones that have come to mind.
So that's 12 easy counterexamples to your completely made-up nonsense about long coaching tenures not happening except 50 years ago, later amended to the late '80s or later when I showed the 50-years-ago assertion was nonsense, later amended to the salary-cap era when I showed the late-'80s-or-later assertion was nonsense. You keep moving the goalposts, and even with the moved goalposts, your wrongness on this point continues to shine.
Why do you keep citing coaches that died or retired before the salary and attempt to prove you're smart and I'm stupid?
It's not an attempt to prove I'm smart and you're stupid. It's simply presenting facts to show your assertion, even in its modified forms, is just wrong.

If that makes you feel stupid, that's not my intent. I recently took responsibility for a completely incorrect assertion I had made around here. My point still stood in that case with the corrected information, but I had made an incorrect statement, and when another person here called me on it, I was embarrassed, but did the only ethical thing: acknowledged that my initial assertion had been wrong in a reply to the comment that pointed out my false assertion, edited my comment with the incorrect assertion in a way that made it clear I had edited it, and added an edit note explaining that I had stated an incorrect number (I had basically cut Jalen Carter's snap counts in half) and corrected it.
If it
does make you feel stupid, all I can suggest is that the next time you want to move the goalposts far enough that some twisted version of your initial assertion can be technically correct (and that's the best kind of correct!), maybe take a few seconds to check if your latest version isn't still gonna have a $#!+load of obvious exceptions. In this case, you wouldn't have even had to look up the coaches individually. You could have just looked at the dates on the list of coaches in the comment to which you were replying.
I know what happened to those old white bullies after the the salary cap and free agency especially when they made it hardcop do you?
I'm not sure what this means. But I've just presented an off-the-top-of-my-head list of 12 counterexamples to the third version of your still-incorrect-even-with-moved-goalposts assertion, 12 guys with long tenures as head coaches in the salary-cap era.