"I'm a believer"

Personally the front end like the digital front end equally important  for quality for it provides the music good or bad , if the quality is not real good it cannot be made up down stream.

Simply because a boutique audio manufacturer produced a mega buck product that conforms to their idea of a “reference” sound, does not equate to that product being tolerable in your personal system. 

 $20k for a cable that makes things sound just a touch better 

You couldn't have described the  "Rule of Diminishing Returns" any better!

Room dimensions, furniture, occupancy of the room, wall hangings, open or closed door and the list goes on and on. All these with even the most minute of change are factors in what we hear.

Because most people never tried to acoustically control a room , passively and actively with mechanical devices as resonators. they cannot imagine the deep audible powerful impact of the presence of even a single straw of specific dimension and location in a room .. Period...

Remember that a speaker is a resonator among possible other resonators in the room ...their distribution matter ...

I too have heard speakers that alone double my investment in my whole system, and walked away thinking ‘what am I not getting’ for that kind of money. And others times I hear speakers that I would think of as small room system speakers and thought ‘why in the heck did I spend what I spent’ .

The reason why this is so, is because the acoustic control of the couple speakers/room/ears is the main factor in audio not the dimension of the speakers or his price tag or even measured specs ... Any speakers well designed of any price in an adapted room will sound at least reasonnably good if you give it to someone knowing basic acoustic ...

It will reach and pass the minimal acoustical satisfaction threshold ...This threshold exist not only subjectively but objectively ... As the diminishing returns threshold which is also a subjective/objective FACT determined by subjective history of the owner and objective qualities of the design and acoustic coupling ...

It's the ROOM!

In my experience, any speaker or other type of audio equipment will only truly shine in a properly treated room.