Excessive camber, either negative or positive, make the tire want to conform to the shape of a conical section.
Toe is the primary tire wear angle. Unfortunitely too many alignment techs have taken the attitude that all they need to do to set an alignment is "set the toe and let it go". In so doing they all to often miss additional significant problems.
One of the most critical factors to this discussion is that alignment is not a static thing. Alignment is dynamic. The attempt to setting alignment is to somewhat guess at what will end up being appropriate when the car is in motion, not sitting on an alignment rack. Toe changes with road force and drivetrain power. Caster and camber changes as the vehicle bounces up and down and as it corners. Alignment also changes some just from the additional weight load in the car and how it is distributed. One of the most critical lessons taught in a basic alignemnt class is that if you are aligning a car that has a very heavy driver, it is best to have the driver in the car while making adjustments so you can compensate weight induced pull or wear.
So why do you have good luck with some cars with fairly extreme camber settings? I don't know. Maybe you spend most of your driving time taking hard corners at higher than normal speed? Maybe you carry 500 lbs of mountain rescue gear in the trunk that wasn't there when it was aligned? Maybe the alignment gods have taken a liking for you and have given you special dispensation? Whatever it is, I can clearly say that it is uncommon to have so much negative camber and not have tire wear. After all, your tires don't start life shaped like a conical section.
