Wolfenstein 3D was ray-casting, not ray-tracing. There is quite a difference between the two techniques.
According to the wikipedia ray casting article, the two were used interchangeably "in early computer graphics literature", just to make me feel even older.
I think you have it backwards. Ray tracing is O(#of pixels*number of light bounces). More common 3D rendering is based on O(# of objects in the scene). It's conceivable that ray tracing can be more efficient for scenes with many objects.