Budget High Current Power Cords

This post/query raises an interesting more general point.

Some companies sell a range of one-size-fits-all power cords, only differentiated by construction and price.

Others sell power cords designed for higher power and lower power applications; sometimes there are different "versions" of what is otherwise the same model.  Almost always, the high power versions are constructed with smaller awg (i.e. thicker) wire.

So, who is right?  If some companies believe the same awg is more than adequate for all applications, are other companies just taking advantage of the situation to charge more for more copper (or whatever).  Or...?

Cerious GE power cords are offered in 3 versions for type of use, but all are priced the same...

twoleftears +1 excellent question.

@twoleftears  I tend to believe it more along the marketing lines than what is actually necessary. IE, used commercial / industrial  circular saws when I was in business (Builder/contractor/carpenter I used 12ga electrical cable to run my saws which drew 13-15 amps. A typical amp draws 4 -5 amps. Consider that back when most things came through with an attached PC, the ga was 14-16...many were 16 gauge. That said, I believe that PC's do make a difference. But I doubt I need a 7ga or 10ga for my amp, even though I have one now

I am rolling with the Signal Cable Silver Resolution at 12 AWG for my X200 and their Magic Power Digital Reference 12 AWG and has double shielding for my CDT and DAC. Not overtly expensive by any means. 
http://signalcable.com/power_cables.html
Just because I am frugal. Rather spend money on music and my kids.