True. However, my point was that the invention of the wheel was a lower tech achievement than (apparently) the numbers system of the Incas and that it is short-sighted to measure a civilization's techonological worthiness soley on whether or not that civilization used the wheel.
Yes one must look at the big picture and clearly the wheel was not their sole technical or cultural lack else their civilization would not have been vanquished so quickly by a much smaller force at arms.