@analogj, no I wasn’t suggesting that only the power cord is critical in helping any systems SQ. The power cable in conjunction with a good power conditioner should work together to help keep the electricity running through your mains clean. A lot of what will work best in any system can depend on system synergy, the compatibility of different components to work together for the most optimal sound.
For example @markiew commented that for him the Puritan 156 did more than an AudioQuest Niagara 3000 and an AQ Hurricane power cable in his setup.