Marketing helps with familiarity, and the Air is unfamiliar and relatively expensive.
The sales of the 17 line are still well below the Pro's. But it's familiar, and every review, article, etc. is talking about how it's the best value iPhone ever.
The Air is unfamiliar, and when people go to apple.com, they see this unfamiliar device that's more expensive than the 17 and close to the Pro, and they know nothing about it - so why would they choose it? People don't like change, especially with phones. Marketing could help with that unfamiliarity. I'm not saying it would make the phone a huge success, but throw a few commercials in some primetime TV spots and that will garner some buzz.
Some might be, but not all. It's an interesting study in sales/logistics/marketing as a whole, regardless of your opinion on the Air.
Great point, and very true, but I'll revert to my first point above - marketing helps when you have something new.