If Power Cords Don't Matter...

First of all, I don’t own any high-end power cords, mostly because I can’t fit them behind my rack. Second, I am not trying to stir up controversy, as you will see from my question. I understand that the people who believe power cords make no difference argue that once the power gets into the component, the AC is converted to DC and the power supply of the component takes over completely. I think I have that right for the most part. So it that’s true, and it probably is from a traditional EE standpoint, why is it that I have not heard anyone say that power conditioners make no difference? I am not aware of anyone with a decent system ever saying that a Niagara or Triton or Audience teflon conditioner didn’t affect their sound, for good or for bad. So if the EE theory is true, wouldn’t power conditioners make no difference either? I have an Audience AR6T for almost 10 years and I think it made a big difference. BTW - I am not talking about Power Plants, which deal with voltage stabilization, which is a different topic.  Obviously, if your AC voltage is way off, it's going to cause problems.  
The weakest spot of power cables is not the wire itself, and not the power plug or the inlet plug, but the termination of wire to either of them and the mating resistance.  It is seldom done right and at full load these connections heat up quite a bit.  Here is a thermal image: https://www.onfilter.com/cable-temperature  The cables are industrial-grade with C15 and C19 inlet plugs.  The loads are ~15A and ~20A on each correspondingly.  You can see that wire itself isn't a problem for heat dissipation, but the connections are - it is hard to discern between the temperature on wire connection to the metal parts of C15 and C19, or the mating parts of the connectors.  Whether this affects the sound is in the ear of beholder, but the lower the heat dissipation, reversely counted, the lower the resistance, and theoretically lower  minute AC voltage variations based on load current.  If you are curious to test it yourself, we use FLIR One Pro for these images.  

I am not understanding what you are saying in your posting below. In high school physics we learned that voltage is analogous to physical water pressure, and current is like water flow in volume. So what you are saying is losing me.

I do believe power cables can make a difference, especially going to from the very basic inexpensive ones to ones that are made for better hifi gears.
danager, congratulations on trying; it makes all the difference.  :) 

Just wait until you work up the nerve to try a comparison of sets. I suspect you will be scratching your head for a long time about that.  

Power cords - glider
Sets - rocket propelled 
I am not understanding what you are saying in your posting below. In high school physics we learned that voltage is analogous to physical water pressure, and current is like water flow in volume. So what you are saying is losing me.

I’m losing you because you’re missing my sarcastic sense of humor. Mr EE lectured us on how electricity is "not like that at all." There are important differences. But instead of taking time to explain any of that he shows off with his clever little insult. I get accused all the time of talking down to people but here we have a guy who starts right off with people "who don’t have a background in EE think electricity is like water, but that is a wrong analogy." Sheesh! 

Wrong. It is an imperfect analogy. But it for sure is not wrong. As my witty little reply makes painfully clear.

I even swapped around gauge of wire with diameter of pipe. The analogy is darn near perfect. Voltage is exactly pressure. Just like water. We even call amps current.

Even getting into math, the analogy continues impressively well. V=IR is voltage equals amps times resistance. Substitute pressure in lbs/sq in for voltage, liters per minute for amperage, pipe flow resistance for ohms, the analogy is almost one for one. Far from wrong.

Imperfect? Certainly. Wrong? Not even. Item #269 on the list of why we would all be better off to ignore credentials and learn to think for ourselves.

PS- troidelover, did you spell it wrong or was triodelover already taken? ;)
Charyro is correct.  With respect to say  amps and preamps, if your AC supply voltage is grossly correct and consistent, boutique power cords and power supply conditioners are unnecessary because the amplification devices, tubes or transistors, use DC current which your amp or preamp produces from its power transformer, rectifier and in some cases, its voltage regulator.  So if you want to improve the quality of current presented to these amplification devices, you would have to optimize components within the amp or preamp, the power transformer, rectifiier or voltage regulator, not add on external tweaks like boutique power cords or power conditioners.