Its not that its simply a matter of being a few feet between all the wiring in the wall and your equipment, saying the last few feet don’t matter. Its that the last few feet can mess up between the wiring in the wall and your equipment. Stock cables can degrade what is coming from the solid cable in the wall. That’s the point I believe some do not realize. Better cables do not "improve" the sound. They avoid messing up the sound... Then there are some cables that can color the sound in appreciated ways. Stock cords can simply be bland in comparison. The ideal connection? Would be having many outlets from the wall with the inside wiring extending out to the equipment without a power cord. Shielding can matter. Stock cords are generally not shielded.
Let's talk power cords
Does a upgrade really make a difference over a stock cord?