I think this is the guts of where this article gets it wrong.
But opinions are one thing. The speaker industry is probably unique in the high-tech consumer products field in that its followers—amateurs, admittedly—actually think they can design and build the product themselves. They often think they can do it better than the speaker company itself!
No one would ever try to build his own Mustang or his own iPad from scratch.
But give someone access to a good cabinet shop, a Parts Express catalog, and the latest edition of Vance Dickason’s Loudspeaker Cookbook, and look out! Vastly superior speaker systems are right around the corner.
I think the art of designing and building a speaker system for the home, is much more akin to the organ builders art, not the car maker. Cars are utilitarian devices.
Organs on the other hand are all custom and voiced to the space.
Let me enter in to the discussion in a little more depth.
For instance take these surround speakers. This one is away from the wall.
This one is in wall.
The crossovers in the two speakers are different to account for the differences in position relative to the wall. Also the lobing pattern of the speakers has been optimized for their position, so that the speakers are actually beaming down over the listening area, with as wide a dispersion as possible. Not a winning commercial proposition.
Speakers and room architecture are an integrated package really no different from the organ builders art.
Now lets take a bigger challenge in which I don't think any off the shelf speakers would work well.
For architectural reasons this was the best solution for this very nice space.
Not very promising. But the DIY builder/designer can optimize a speaker for a difficult location and application.
The speakers are ported, but I did not want them so sound like it.
So the speakers have a F3 of 55 Hz. That would not look promising on a spec sheet would it?
However my alignment is unusual with first order roll off to 30 Hz, so the speakers are only 6 db down at 30 Hz and then roll off fourth order. The speakers are over damped slightly.
Now the subs and crossover are designed to match. So what is required are subs that will provide half the output at 30 Hz and then roll off rapidly above 60 Hz. So the subs are compact isobarik coupled cavity design, with an F3 of 27 Hz rolling off second order. In this design, even though ported the designer has great control over Qtc, and the Qtc of these subs is 0.5. So they only cover an octave and a bit. That is all I need. With the natural roll of of the band pass subs and the active filter they roll off fifth order above 60 Hz.
The point is that as said those subs have very limited application.
In addition I can use a long discontinued driver, the superb KEF B139 from about a half century ago. No driver of that size since then has given such excellent bass performance. I chose a driver that the owners of Dynaudio very kindly made available to me as a personal favor. It covers from 400 Hz to 4 kHz, and crosses to a mylar ribbon at 4 kHz. Music and speech are excellent.
The design also allowed me to give a nod to a mentor Raymond Cooke, founder of KEF, as the design suggests an appearance of the KEF line of long ago.
This is a large space, with a lot of open areas, but this system fills it adequately with a very nice bass that never booms. It is excellent for speech and music.
I use it a lot in the long cold winters, and I really like spinning vinyl, as I used to do that by the fire so long ago in my youth back in England.
The point of all this is that once the DIYer has sufficiently mastered the art, he has options, that the purchaser of off the shelf speakers can not even dream about.