I've known about the issue you speak of since 2006, when I bought my 2007 Nissan Altima, with the 2.5 QR25DE engine in it.
The most common failures that you are describing are on the Altima's with the QR25DE engine.
Because these engines don't use an EGR system, they use valve overlap between the exhaust cam and intake cam timing to allow for exhaust gasses to be reintroduced into the combustion chambers, to lower the temps, and decrease the NOx levels that the engine emits.
The very early cars, in the year range that you described, ran their engines very lean, to get very good fuel economy numbers, and held the variable timing longer to get a larger pull of exhaust gasses into the combustion chamber to lower the NOx amounts they created by running the engine leaner.
Over time, these higher exhaust temps would break up the pre-cat material on the leading edge of the catalyst, and during the EGR function, that catalyst material would be introduced into the combustion chamber, and would basically sand blast the walls of the piston bore. This increases the clearance, leads to scuffing and gouging of the cylinder wall, and eventually you have introduced enough wear to allow for excessive oil consumption.
Any owner of these cars who isn't diligent with checking their oil level, and regularly changing their engine oil is bound to run the engine low on oil, which then trashes the rest of the engine.
This is common, and well known in Nissan Owner circles.
The 3.5 V-6 engines used a normal EGR circuit, and debris would typically get caught into the EGR system, leading to it being clogged, and setting off a CEL. When that light is seen, the mechanic would see the debris in the EGR tubes, and then pull the catalytic converters, and see the damage. Usually, this is caught before damage is done to the cylinder walls, and the V-6 engine cars wouldn't have complete failure like the 4 cylinder engines exhibited.
So, do what you will with the information.
There's NOTHING you can do to get Nissan to pay to fix your motor.
It was long out of drivetrain warranty when it failed.
At the most, you might have been able to force them to replace the cat under emissions warranty if you had caught it early enough. But you didn't.