This is sort of an unfair comparison. Mogami is a good manufacturer of pro-audio cables (which is a different industry). In this industry, the goal is to make a durable cable that works well in live or even recording studio situations. They are not after the ultra-high end sound that most audiophiles are chasing. Also, the wire material is basic OFC copper that is stranded. All this is decent for what you get. They are generally less expensive (under $150 in most cases, unless you are getting a multi-channel snake or something).
Cardas has a very specific manufacturing method where it uses a very high purity copper and does a slow draw when forming the actual wire strands to make a long grain copper conductor (this is approaching OCC or Ohno Continuous Cast). Also, much of their product uses litz technology where the individual strands are coated in an insulating enamel that makes the "stranded" wire act more like solid core conductors. There is less capacitance since there is no delayed charging of the innermost strand. All these make a much more expensive wire and this can have significant differences in the end result, for those who are critical and can hear the differences.