Puzzled about reasons why there seems to be no shortage of used planner speakers

Why just limit yourself to planar or box or horn etc. Buy used and spread your money out over all varieties you like and take turns listening to each type and move on when you would like a new experience.

My first pair of planar speakers were the Maggie Tympani 1Ds back in the early 1970s.  The were physically huge, required multiple ARC Tube amps to sound their best, and yes, were often mistaken for a pair of dressing screens.  But the sound experience they produced was, and still would be no doubt to this day, truely world class.  

When I moved to a major metropolitan area and smaller living quarters, I replaced them with a pair of Infinity ServoStatics, which were physically MUCH smaller, but sounded terrific, on stands, right up until they would arc-over and need RTR elements replaced.

Later on I moved on to the much more reliable Accoustat 2s, then the 1+1s, and finally the 2+2s and direct drive amps. But no matter what I tried, they still had an artificial, over etched sound about them that I couldn’t live with in the long run.  To my ear, the Martin Logan’s have a tendency toward those those same colorations.

I was very happy with Audiostatics for several years, but no matter what I tried, I never could never get a subwoofer that could seamlessly give them the bass augmentation they needed.

The sound of Carver’s Amazing Speakers caught my ear for a number of years, and the BG Radia with the same ribbon driver was also a keeper.

I have tried all kinds of box speakers  along the way, from Celestion, to KEF, to B&W, and even ARC triamped Fulton J Modulars, but none could ever provide the immediacy and immersive soundfield of planers.

After over 40 years of searching for a completely satisfying sound system, I heard a pair of Sound Labs M-1s at a friends’s home.  Finally, after all these years of searching, I had found the sound quality that I have always hoped would be possible.  

I bought a used pair of Sound Labs M-1s and sent them to the factory to have the panels and backplates brought up to date.  The people at Sound Labs were very friendly and helpful and walked me through the whole process.  For me, Sound Lab speakers and Pass Labs electronics provide absolute sonic nirvana.  I am retired now, and often have 4 or more hours listening sessions, day after day.  The sound quality is so spookily realistic that I am continually amazed at how much more there is to be heard and enjoy on all of my favorite recordings.

Sound Labs electrostatic speakers have been around for so long that, years ago, J Gordon Holt used to use them for his personal reference.  In recent years, Sound Lab has made changes in their panel and backplate design that make them more efficient and even better than ever.  The most recent developments have made it possible to produce the same quality of sound by noticeably smaller sized panels than my M-1s.  

Sound Labs has chosen to remain a niche company, with a small production and only a handful of dealers world wide.  If you buy a pair of their speakers, it will not be because of any advertising or mass marketing on their part.  They are the opposite of Martin Logan.  More like Magnepan.  Much more like Sanders.  You will have to go out of your way to get them, but they are well worth the effort.

By the way, I am not affiliated with Sound Labs or Pass Labs, or anybody else.  I am just a home music lover, who, after all these years, has finally found the almost perfect speaker.   I say “almost perfect speaker” because to me, the truely perfect speaker would sound exactly like these Sound Labs, but would be as small as a Rogers LS3/5a.

You may see many planars for sale- some for good reasons...some for not-so-good reasons. Not sure this topic just gets overthought, though.    

You're about to ride a spiral.  

The LRS ribbon can offer more amazing details- including illuminating compromises you have gotten used to with your existing system.  The contrast of the different sound stage will be aesthetic change.  (Tho, from my experiences,  spouse can tolerate Paganini Violin Concerto w/out running from the room w/Planars. )

What you may have not visited for some time is how many amplifiers do you know of that have >1dB design/peak margin?  What was once inaudible clipping might now become audible.  50 W might've been OK.  To fill your listening space, 3dB takes you to 100 W.  6dB will take you to 200 W.    

As to your venue, (an enclosed, reflective wall/ceiling?) might've given you a +6dB. Hardwalls will emphasize the high end spectrum.  And a ribbon w/ <4' from a wall may cause you to consider anechoic treatments.  Planars are a bit more- forgiving?  

I tried the Apogee Scintilla (1 Ω) but, even hernia-weight amplifiers (Krell 250) still wasn't enough. Many Krells were sacrificed to Tūtū Pele trying to feed Scintillas.  Yes- this LRS is 4 Ω...but let's see what happens above 4kHz. Unless LRS rolls off the high end....

look at all the use Drivers
cone speakers on the market.  you better get some power  if you want to play with ELS, Ribbons 
 stuff like that you can't be a pussy going that way