Rubbish. How on earth does a distribution channel limit ones marketing ability? These are completely orthogonal aspects of producing a successful product.
Do you think movie studios hope that you'll stumble across their film by looking at the show times of your local theater? Do Authors pray that you'll stumble across their book in the M-R fiction section of a bookstore?
Unfortunately, smaller independent films and authors probably do hope you stumble upon their works -- it's notoriously difficult to sell books unless you are picked up by a major publisher.
I think his point is that things like the App store should be more of a meritocracy (like the web), but it's becoming increasingly difficult for smaller players to get noticed to due the economics (strong downward pricing pressure) and Apple's policies (random rejection can destroy months of work). One thing they don't mention is how difficult it is to figure out where your sales are coming from; there's no Google analytics or referrer logs for app sales -- you have to do things like become your own affiliate through LinkShare and assign different codes to your own links if you have multiple distribution channels.
A list of all the things one can do to raise the profile and track the marketing of a single developer app would be a useful resource. Hell, if you put together a decent sized ebook, it would probably be a reasonable successful product. If you could reach the right audience.
You're right that the App Store distribution channel does not limit a developer's marketing ability. It does, however, limit the pricing. The App Store is structured to directly reward high sales with exposure, creating a feedback loop that drives prices down. As an indie developer, I can support a modest marketing budget that creates modest sales if I can charge $29 for my app, but I can't do it at 99 cents.
Not all distribution channels are created equal, and this particular one is so biased toward high volume/low price that an indie can't get any traction.
The distribution channel for SmartPhone software is the Internet. You don't see BlackBerry apps being sold at retail B&M stores in tiny little boxes. Developers sell their apps usually through a web site with their own checkout system that delivers a binary to the user who then must figure out how to install it. With the iTunes store the first part of the model should be the same -- the developer creates a web site and promotes their application through ad buys, promo copies to reviewers, and whatever other tactics they think will work. The only difference is the checkout stage would link to the iTunes Store URL to complete the transaction.
I think all these developers are really missing the point that built in App Stores on devices are simply a delivery medium. You shouldn't rely on it to be a discovery medium for potential customers.
As I note in my comment above, the App Store is not merely a neutral distribution conduit, it is also (by far) the primary discovery medium. The vast majority of app shoppers buy from the top lists. And the top lists are systematically structured to promote high volume, which causes devs to lower their price. That's why even the EAs of the world are calling on Apple to at least go by revenue rather than units.
The App Store is 'simply a delivery medium' only in the same sense that Fox News is 'fair and balanced'.
