Power cable education needed


Hi everyone. I need some education on power cables. I have been reading that a good power cable is vital to a good sounding system. If that is true wouldn’t the companies the make the components include a good power cable to insure their product sounds the best that it can ? Should I evaluate the power cables in all of the components in my system? 
ronboco
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I also am considering my room. Does there come a time when tweaks stop being able to be heard because of the room? Is my room good enough to continue upgrading ? 
I personally know families of four whose monthly food budget is less than your "low budget" power cable, and not a single post here can articulate what exactly the return on 'investment' is.
When someone says they couldn't believe their ears when they tried a $600 cable, they're either selling snake oil, or trying to convince their wife that they didn't buy snake oil. Again.
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