Diminishing Returns: Cabling

[Intamin]

I think we can all agree that with audio diminishing returns exists. I was wondering if there was a consensus as to where this comes into play with interconnects/power cables. For example, is the difference between Nordost's middle of the line interconnects to their Odin or Vallhalla interconnects huge, or is it a tiny difference (for those with experience)? Does diminishing returns kick in at a lower level with interconnects, or is there still a lot to gain with advancement through manufacturers' interconnect series?

PS: I am not talking about speaker cable.