Do you think audiophiles are the most gullible hobbyists

As to what thing seems preposterous, too preposterous to ever consider, I suspect it all depends on the thing being considered and the person doing the considering. There are a lot of things in audio that were once considered absurd or preposterous that are now commonplace or at least relatively common. Things like vibration isolation, tiny little bowl resonators, hi res downloads, WA Quantum Chips, Schumann frequency generators, CD enhancers, CD demagnetizers, cable elevators, fuses with directional arrows and scattered laser light absorbers. I admit Mpingo discs, Silver Rainbow Foil, Lessloss Blackbody, the Red X Pen and the Teleportation Tweak are probably not going mainstream any time soon.

PT Barnum once opined folks would be much better off generally speaking if they believed in too much rather than too little.

Ejr1953 wrote,

"Ions ago I had some really professional sales training, where they differentiated "need" from "sense of need"."

One assumes those were negative ions ago.

I am thinking of HL Mencken, who said, "Nobody every went broke under-estimating the intelligence of the American public".  Or of WC Fields, who said, "Never give a sucker an even break."

I guess we audiophiles are no worse than any other devout hobbyists, American or not, and no better.  

There are more suckers in the USA than others places for a simple reason.
 We are so brainwashed from cradle to grave  that reality just does not register with us .