I have to disagree about camber not causing tire wear on street driven vehicles. I'm an alignment mechanic by trade, and have seen the effects of incorrect camber. 2-3 degrees one way or the other, depending on vehicle specs, won't waer tires to much, but if there's an issue with the cross camber not being correct, or if it is beyond the 2-3 degrees, it can wear tires very rapidly.
One other thing, another reason that the toe is set in on rear drive vehicles is to counter the effects of the thrust caused when the vehicle is driven. The thrust forces tend to push against the joints, by setting the toe in, it allows for the slack in the joints to be taken up without loosing the toe setting.
