Negative camber can contribute to tire wear, but it gets a bad rap IMO, as I don't think it is usually the problem in and of itself, assuming that the suspension isn't bent or worn out of spec. The problem is that people can see negative camber, simply from standing at the back of the vehicle, so it gets a lot of attention. What happens is that the tire deforms, and doesn't just sit on the inner edge. But people tend to think that it does just sit on the inner edge, and that that is what causes rapid wear at that location. If it did, and was in fact a design flaw, then it would be very difficult to explain the good tire life results from those of us who haven't had rapid wear on the inner edge, despite having the same designed-in negative camber. I traded my X5 in with 70,000+ km on it, and the original tires were still good. 17" in my case, not 19", but it is still telling.

What usually causes rapid wear on the inner edge of the tire is toe-in, the tires being pigeon-toed and not pointing straight ahead. This is also adjustable. If the tire is pointing inwards a few degrees, but is forced to roll straight (in line with the vehicle), then both the inner and outer edges are continually slipping (skidding), only the centreline of the tire is rolling without slipping. Both inner and outer could theoretically wear, but the inner tends to wear more, due to the negative camber. Fix the toe-in, to the minimum of the spec that BMW publishes, and you will often get much better tire life.

With wider tires, the toe-in problem is amplified. Also, sport tires often have softer compounds that wear faster anyway.

Only trouble is that you can't see the toe-in (the vehicle is in the way) so you will still get discussion about the negative camber, which you can see easily.

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2007 X3 3.0si, 6 MT, Premium, White

Retired:
2008 535i, 6 MT, M Sport, Premium, Space Grey
2003 X5 3.0 Steptronic, Premium, Titanium Silver
2002 325xi 5 MT, Steel Grey
2004 Z4 3.0 Premium, Sport, SMG, Maldives Blue