Are you trying to sell it anywhere besides the forum classifieds? (I just looked at your ad there.) The exterior shots look pretty good, actually. There's only one rather poor photo of the interior, turned sideways... that may put people off.
I see that you've had it listed since February on the Airstream classifieds. That means people like me might not have seen it since then, because I generally click the "last 7 days" button just to see what's out there. When I was hunting, I was checking daily but really only looking either at the last day or the last 7 days.
You might try eBay, and perhaps list it in PHX and Tucson Craigslist. If you list it in Craigslist, expect a fair amount of crazy contacts offering half what you're selling it for and some offering 3x what you're selling it for but you're supposed to send them the change after you get their cashier's check in the mail, etc. Don't do any business via Craigslist with anyone you're not looking at face-to-face, but that's where I found my Argosy trailer.
Really, the exterior looks good. Take some honest pictures of the interior, list what's right and wrong with it, and DON'T list it for the minimum you'd take. Especially in the Craigslist world, it seems like most people are happier to pay $7k for something listed for $9k that's worth $7k than they would be to pay $7k for something listed for $7k that's worth $8k. Like an auction, it's more about the "win" than the real value.
Il Carriaggio — 1975 Argosy 24 | Il Progetto — 1976 Argosy 28 Center Bath | WBCCI# 15566
He has all of the virtues I dislike and none of the vices I admire. — Sir Winston Churchill