Of course.
But even with the slop of a volume-leveled, friend-assisted single blind test, it can be pretty revelatory to your average home audio enthusiast.
Agreed, but really at least there you actually have a sort of control group. That is really important.
The control is your previous findings sighted on the same products. Very flawed but better than no control at all.
Ideally if you are testing say 4 products, you group is large enough that some listeners never even hear more than 1 product, some hear 2, some 3, some do get all 4.
Might be fun to involve this somehow at how.
I don't mean to be rude, but the people claiming no differences DAC to DAC - have they owned one in the $500-1000 range? You don't see audiophiles making the opposite move to a $150-200 device with better measurements. I could easily hear what was different between my old Topping D10 and the E30 I recently received. Having lived with the D10's sound signature for four months, I knew something had changed and I could tell you what it is.
Actually I do see people all the time that are moving to less expensive gear that offers similar or the higher performance. There is also a definite line zone of very diminished returns even if still making "some" gains when spending more.
That move to buying the same quality for less however is a major problem for many companies who rely on you moving the other direction so they can still make good $. But this is really business right? Someone undercuts you and now what, you can't complete on real quality anymore?
Well a fool and his money are soon parted so one strategy is to appeal to lack of confidence. There is a business strategy to sell things for higher prices to instill confidence in a trusting (foolish?) buyer. With technology is it easy to do. I am not saying this is universal but be aware of the power of confirmation biases and marketing and all.