Fella wrote:

"The learning effect ... this is one aspect of human hearing the
DBT/ABX
protocols needs to address if they are to ever become accepted as
scientifically valid methods of testing the differences between audio
products."

IF THEY ARE TO EVER BECOME ACCEPTED AS SCIENTIFICALLY VALID METHODS?

My good sir, they are already accepted as scientifically valid, by
everyone except a tiny minority of high-enders.