A cable like mogami is certainly much better than let's say a Dr Morrow, or Kimber, or audioquest, because in the mogami, you get a good chunk of pure copper kept all together whereas in the others, the cable is made of individually wrapped smaller conductors, therefore a lot more plastic and copper in contact with dielectric which is bad. It 's actually so bad that audioquest felt the need to slap batteries on their cables.
Dr Morrow is more plastic than copper. I don't get it.