This is very timely...

I really enjoyed the article.  I hadn’t seen Butterworth in print lately, and it appears he has moved to headphone world, which just isn’t for me.
  I agree with most of what he says.  I have no opinion on the high sensitivity speaker issue.  I am however a big fan of Room Correction and Subwoofers, and their dismissal by most of the Hi End community is for me just one of the curious traits of this hobby. Other difficult to understand issues for me have been the (initial) abject praise for MQA and the use of exotic materials in speakers.
  He doesn’t touch on the main reason for decline of the Audio Industry, which is that people just don’t care.  In the seventies my contemporaries were greatly concerned with having a decent system, and most of us couldn’t afford bupkes.  My friends now have much more disposable income and now use Apple buds, cheap Bluetooth devices, or perhaps cheap AVRs.  Television speakers satisfy them, or if they upgrade it is a soundbar.  The lack of interest amongst the millennials and Gen Xers  is well documented .  In response the High End manufacturers chase the declining number of senior audiophiles or else listeners in the far east.  It isn’t a healthy trend

The high end market actually has more potential customers in the far east than they ever had in the west at any time. It's a status symbol in parts of Asia.

If audio writers who praise these products asked mainstream speaker designers why they don’t make super-efficient speakers, they’d learn that with efficiency comes compromises—in frequency-response linearity, dispersion, distortion, and power handling. Few highly efficient speakers achieve a respectably flat frequency response and broad dispersion. And many of the primitive tube amps that are typically used to drive them have very high output impedance, which will interact with a speaker’s impedance to change the sound in ways the speaker’s designer didn’t anticipate and likely wouldn’t condone.

This author doesn’t have idea what does he talk about. His technical knowledge is zero. High efficient speakers don’t have the thermal distortions. These distortions cause compression, significant frequency response changes on different loudness. High efficient speakers don’t need power more then a single watt.
SET amplifiers has the lowest distortion on low power (first watt). SET have the lowest distortions, no high order distortions and transistors thermal distortions.
Bottom line, a proper built highly efficient speakers with SET amplifier system sound most close to the real classical or jazz music performance.

Yeah, that is the dumbest thing I ever heard in audio. I've had people tell me the midrange is perfect and seamless- and this is with tubes.   https://www.youtube.com/watch?v=q6xMt6Wj9JE   Sure there are probably some highly efficient speakers out there that have problems. There are also some poorly built tube amps that give tubes a bad rep. But that in no way justifies any of this blanket condemnation that tries to say these things cannot sound good at all. If you want to take that approach then everything everywhere is crap so why bother at all? Just about as wrong a wrong can be. 

I want to add that extremely flat frequency response and extremely low distortions don't have correlation to the real listening. The religious belief in measurements shows the incompetence of the author.