So do these original 1st pressings, like the mobley soul station on ebay, receive such high bidding because of collector instincts rather than audiophile ones?
Yes, I think you have it right, collect ability and rarity.
I have some Blue Note West 61st street originals, among my favorites is Lee Morgan "Sidewinder."
However I just received this week, Lee Morgan "Candy" and Lee Morgan, "Volume 3", plus John Coltrane, "Blue Train" (the last two are mono) as reissues from Classic Records.
In a word, they are absolutely stunning
If you want the music and the titles are available at Classic Records as reissues, you can save yourself a ton of money, be guaranteed a dead quiet pressing and wonderful sound.
We should support their efforts in issuing these ultra high quality pressings of great American jazz.