I agree absolutely with getting the room right is far more important than cables can possibly be whether they make a difference or not. As for cables, there are things we just do not know and might not for generations to come, real science is a bunch of theories tested until something works out and tested again and again to find improvements. It is a never ending cycle thus we are not at the end of any of it yet and should never assume we know all there is, about anything. It is not a dead end Dogma which happens far to often in nearly all things humans do and it is only a tool to maintain the status quo, not to further enlightenment into the yet unknown.
Are there those that cannot hear a difference, sure, why not, good for them actually. Are those that can, I am sure there are, good for them as well. Are there those that believe there is a possibility of improvement, sure there are, I am one of them and have personal experience to the level I am comfortable in.
Instead of arguing over such a trivial pursuit it might be wise to invest some of that time and energy into things far more critical to the betterment and survival of all things living which includes everything.
Rick