Help me understand "the swarm" in the broader audiophile world

I'm still fairly new out here and am curious about this Swarm thing. I've never owned a subwoofer but I find reading about them--placement, room treatments, nodes, the crawl, etc--fascinating. I'm interested in the concept of the Swarm and the DEBRA systems, and I have a very specific question. The few times I've been in high-end, audiophile stores and asked about the concept of the Swarm, I've tended to get some eye-rolling. They're selling single or paired subwoofers that individually often cost more and sometimes much more than a quartet of inexpensive, modest subs. The same thing can be said for many speaker companies that make both speakers and subs; it's not like I see Vandersteen embracing the use of four Sub 3's. 

My question is this: do in fact high-end stores embrace the concept of multiple, inexpensive subs? If not, cynicism aside, why not? Or why doesn't Vandersteen or JL or REL and so on design their own swarm? For those out here who love multiple subs, is it a niche thing? Is it a certain kind of sound that is appealing to certain ears? The true believers proselytize with such zeal that I find it intriguing and even convincing, and yet it's obviously a minority of listeners who do it, even those who have dedicated listening rooms. (I'm talking about the concept of four+ subs, mixed and matched, etc. I know plenty of folks who embrace two subs. And I may be wrong about all my assumptions here--really.)

Now, one favor, respectfully: I understand the concept and don't need to be convinced of why it's great. That's all over literally every post on this forum that mentions the word "sub." I'm really interested in why, as far as I can tell, stores and speaker companies (and maybe most audiophile review sites?) mostly don't go for it--and why, for that matter, many audiophiles don't either (putting aside the obvious reason of room limits). Other than room limitations, why would anyone buy a single JL or REL or Vandy sub when you could spend less and get ... the swarm? 

duke,  thanks for your interest in helping. My room is an open basement with dimensions of 17’-6” wide x 32’ long, with 9’ ceiling. My theater is an area at the front of the basement with dimensions of 17’ 6” x 14’ . Pretty big space.
Thank you, jdlynch. That’s a big space. Imo you can probably get good results with three subs, since the space is so large.

Okay, here’s what comes to mind:

Add two more subs, which probably need not be as big and as capable as the Submersive, and spread the three as far apart, asymmetrically, as you reasonably can. Bonus points if you can elevate one so that it’s closer to the ceiling than to the floor. You might find that having a significantly different phase control setting for one of the subs is helpful. Perhaps the one farthest from the screen.

Duke, will I need to get some device to set delays and levels for each individual sub? This is where I would get lost.
Hello jdlynch,

     Since Duke hasn’t yet replied, I thought I’d give you my input and advice.
      I use the Audio Kinesis Debra 4-sub DBA in my system and room for about 40% 2-ch music listening and for about 60% 5.4 home theater surround sound audio. My main goal is for very high quality bass for both and the 4-sub DBA concept definitely provides this to near state of the art levels in my system and room.
You’ve stated your basement system, however, will be used about 90% for HT and your main goal for a bass system is more about providing powerful, room shaking and chest pounding bass.
     Duke, knowing the 4-sub DBA concept’s main attribute is its high quality bass, provided the good advice that a better solution for the higher amplitude bass you prefer would be to add 2 larger and more powerful subs to your system and create a custom 3-sub DBA system as he described, although the 2 additional subs do not have to be as large or powerful as your existing Submersive sub.  You would gain more bottom end power, impact and more powerful dynamics by adding 2 slightly smaller and less powerful subs while also gaining some DBA benefits such as increased bass detail, lower distortion and more seamless integration of the bass with your main speakers. 
     In giving his advice that you needn’t add 2 more subs as powerful or as large as your existing Seaton Submersive sub, I believe Duke was referencing Dr. Earl Geddes, the inventor of the 4-sub DBA concept, and his subsequent research and claims that 3 subs in a distributed array can be as effective as 4 subs in a distributed array in some rooms.
     I completely trust both of these men’s advice but I have no experience utilizing 3-sub DBAs, only 4-sub ones, and I’m therefore hesitant to offer advice on 3-sub DBA usage. I can tell you that I’ve adjusted the level of my 4 subs but I’ve never adjusted, or even felt the need to adjust, their delay settings. Volume, crossover frequency and phase are the only required settings on an AK Swarm or Debra 4-sub DBA, I seriously doubt it would be different on a custom 3-sub DBA.
     You may be interested in utilizing a $200 Mini DSP unit, however, which requires a single pair of L+R channel inputs and allows the connection and advanced control settings of up to 4 subs. I believe it would be very useful on custom 3 or 4 sub DBAs but unnecessary on AK Swarm and Debra 4-sub complete kit DBAs.

Best wishes,
@jdlynch wrote:  " Duke, will I need to get some device to set delays and levels for each individual sub? This is where I would get lost. " 

First, apologies for being so slow to reply.   I hadn't checked in on this thread in a while and didn't realize there was a question waiting for me. 

Imo setting delays individually would not be necessary, as the Swarm obviously gets away without them, and I don't think 3 subs instead of 4 would be any different in that regard.   

If you are using individually powered subs then setting the level of each should be easy with the controls.  You might need the Submersive to be a bit louder than the other two since it's the only one that goes real deep, but then again you might not either... trial & error.  

Imo it might very well be beneficial to be able to adjust the phase of the other two subs.  As a starting point I'd suggest setting one of them (perhaps the one farthest from the main speakers) to a very different phase setting than the other subs, like maybe even 180 degrees.   You might want the out-of-phase sub to be at a different volume level from the others (maybe a bit lower), and then again you might not.