For one, they don't recreate a normal listening experience.
There's absolutely no reason for them not to. The only necessary difference - you don't know what hardware you're listening to. But why should that matter?
What if our best listening isn't when we think we're listening critically?
What do you mean by "best"? If you mean "detecting small
differences", then you want typical DBT conditions. Highly focused attention, immediate switches between stimuli, etc. These are all designed to MAXIMIZE our ability to detect small differences. A century of auditory research has converged on these procedures. The only reason people say these rules don't apply in AV World is because the results go against their preconceptions.
If by "best" you mean most enjoyable, the kind of listening we should be doing for ourselves, listening to music instead of listening for differences in sound - then no, DBT isn't the way to go. But that's a completely different issue.
As for noticing subtle details...If you're talking about discovering them in music, you'll want normal listening conditions. If you want to detect
differences in how that already-known detail is reproduced with Speaker wire A vs B, you want DBT.
