Therein lies the rub. They know it, but theyāve never tried it when pressed. Itās a matter of whatās good enough to some not being good enough to others. There is just as much science based information out there as to why IT DOES make an audible difference, but that science is derided while their lack of first hand experience in trying said comparison is put forth as fact, put forth simply to justify a viewpoint without understanding. In the real world, science is based on experimentation and when you canāt explain the results of your experiments i.e. why improvements on the digital source have an impact on the quality of the sound, then you need to further test and potentially change your viewpoint if continued testing and experimentation results goes against your held beliefs. But theyāre not here for that. 
Itās also often out of context because replacing a power supply on a network switch when youāve got a $300 dollar DAC and your entire chain is well south of $2k, youāre more than likely not going to hear the most impact and frankly itās not the best use of your upgrade money in the first place. There are things that you do and gain value from doing WAY further along in the journey and perhaps itās why you get these repetitive argumentative threads. Everyone has their perspective while only one side is unwilling to admit that other perspectives can also exist and perhaps be right.
Believe me, no one starts out saying that a $1500 USB cable will make as a purchase, but for some people at some point in their journey if theyāve gotten that far, it does make a lot of sense. No one should be derided for it but donāt even dare suggest it in a thread here.
The entire hobby is about power, and we se companies separate their power supplies into a separate chassis, but you constantly see comments here about it being pointless to upgrade the power supply to a DAC because bits are bits without having any real understanding of the topic theyāre talking about.
Iād counter that there is just as much damage done to someone starting out in the hobby by the ASR crowd saying that all DACS sound the same and you never need anything more than a Topping or SMSL component (that they provide shortlinks to purchase) because to do otherwise is just throwing your money away. When the reality is that the implementation on these inexpensive (but very good sounding relative to their price) DACs is because their implementation is pretty much the same.
Sometimes it does take a $50k investment to develop a chain that is extremely capable, and it does take years of being in the hobby listening to be able to learn what to listen for. To be able to say that ABX instant switch testing isnāt the optimal way to hear differences because itās not how our senses work. In my journey, Iāve addressed room treatment, Iāve addressed vibration and isolation in components, Iāve addressed power cabling and conditioning Iāve addressed synergy and when I say I hear a profound difference in the continued improvements to the digital source itās because I hear it, donāt have to prove it to anyone. It doesnāt take a lot of money to get a decent DDC and a power supply. Anyone that is open and curious abut furthering their system should know that there are meaningful improvements on the table to be had, regardless of what lacking good faith science crowd says about things theyāve never tried.
The point is that 9 times out of 10 itās best to leave a comment unreplied to and move on.
