Let think about it. If you're saying the cable is the last 3ft, then why would a power supply be any different? That is the power supply is the last one after many miles of cables, just like the power supply cord as the last 3ft, then why a power supply would make a difference at all?
People who are using water analogy and conclude that a power supply cable should not make any difference. But electrons are not water. Before you turn on the kitchen faucet, there is no water in the kitchen in the first place. On the other hand, before you power up your equipment, the electrons ALREADY in the equipment.
Look at the tiny fuse in your equipment. You intuitively think that it has to be the bottleneck but obviously that is not the case. Now if you're using a power supply cable as tiny as the fuse, things won't be very good. Your equipment may not work properly. Why is it that a fuse can be tiny and slim, but not the power cable? Because electrons are not as intuitive as you think.
People who are using water analogy and conclude that a power supply cable should not make any difference. But electrons are not water. Before you turn on the kitchen faucet, there is no water in the kitchen in the first place. On the other hand, before you power up your equipment, the electrons ALREADY in the equipment.
Look at the tiny fuse in your equipment. You intuitively think that it has to be the bottleneck but obviously that is not the case. Now if you're using a power supply cable as tiny as the fuse, things won't be very good. Your equipment may not work properly. Why is it that a fuse can be tiny and slim, but not the power cable? Because electrons are not as intuitive as you think.