Do you think audiophiles are the most gullible hobbyists

I think there is some truth in that, music is among the most powerful of human triggers.
Nobody ever spent a grand for a new book cover that would make Shakespeare better .

OP: With that initial post, looks you are strictly speaking about yourself .

Book collectors are the worst, Jerry, the worst!  

Lots of hobbies have snake oil and those that buy into it

Quite the opposite. Sure there are those who make buying decisions based upon smoke and mirrors but there are - at least it seems to me - more than the hobby's fair share of skeptics. Most are fair. Some are merciless, others are assassins. From what I read in this and other forums it is one of the best aspects of the hobby. Thank goodness for them. 

"Give me a little bit a money
And a few fine clothes
A whole lotta lovin'
And let is be yours

That's all I want, baby
That is to be with you
I wanna love you, baby
If it breaks my heart in two"

Absolutely not! I see little kids being outfitted with $500 baseball bats. Photography, woodworking, automobiles, home design and decoration, women's shoes and purses, computer gaming, name the hobby, they all have their suckers.