I have a feeling that it has to do with the torsional ridgidity of the tire. The more rigid the tire the lower it ability to flex.
generally the inexpensive tires will not be as stiff and therefore the tread will have a higher tendency to flex to better take the shape of the road.
The higher performance tires are stiffer and don't flex as easily to conform to the shape of the road so they tend to take their own path, one in which all the tires are, for the most part, on the same plane.
