That is probably almost universally true!
I have seen a few A vs B video, while I like this guy's presentation overall, I do not believe he actually heard the difference he mentioned in any of his videos, below is just one example:
Anthem AVM90 vs Anthem AVM70! Is the AVM90 WORTH IT? Demos, Measurements & Comparisons! - YouTube
And then this very example:
In this one, noticed what the other gentlemen, Erin and the other one (forgot his name) said too, Erin didn't say a thing if I remember right, because I think he knows better..
AVR vs Separates - Can You Hear a Difference? - Bing video
Youthman himself, cited what he heard better sound from the separate, the lowly 7706, than the excellent top notch Marantz SR8015. The believe separates use better parts and circuitry...blabalaba I really don't remember his exact words. He didn't know the AV7706 uses exactly the same DSP, used in the same year (even precious years to 2017) Marantz and Denon AVRs. So he messed by using better pars (DSPs) to explain why he heard so much better "separation". So, in this case it isn't just price but also his expectation that "separates" must sound better.
If I remember
@Cos was very impressed with the Anthem AVR in the dealer's demo room that he would have been okay with it too instead of the AVM70.
My point it, very often (not always obviously), it's like they said, it's all in their heads!!