"Because they know better and are technicians "
Well what I do know is that engineers and technicians often talk rubbish, and have ears that demonstrate that their ears seem to be pointless.
And if anyone writes that studios have kit a or b so must be good, then that is even more rubbish. If they knew more than not a lot, there would not be so many bad recordings out there.
But back to the original issue, I recently bought a ps audio power regenerator which came with a stock power cable, and the instructions stated that although a stock power cable was included, they recommended "better" ones should be used as they would improve the quality. So an item that cost rrp around £2,900 uses a cord that cost £2 and comes with a recommendation!? As said above, it seems to be a marketing decision as to what to include or not.