I think this discussion is purely academic. By far, majority of people can tell the difference between a good sounding system and a great sounding one. It’s the so-called audiophiles that look for small incremental improvements which may or may not be apparent to an average person.
How are you hearing no difference?
In my experience, I've never heard two pre-amps that sound exactly the same, nor two DACs that sound the same, nor two amps...etc. Yet, occasionally someone will claim that they heard no difference between Product A and Product B in their system. I find it difficult to believe.