(Disclaimer: I don't own an iPad, just an iPod Touch, smartphone is Android, boo me off the stage, etc.)
Apple's policies are onerous, plain and simple.
The magazine on a newstand being more than 30% comparison doesn't really work. Magazine subscriptions (most magazines, anyway) are typically under $2 an issue if you go for a year. Newstand copies are sold at $5-$8. Let's suppose the newstand makes 50% on a $5 copy (you get $2.50) and Apple makes 30% on your $1.80 digital edition (you get $1.20). The 50% retail margin is overboard, considering the Magazine Publishers of America say it's
33.6% average adjusted gross margin for shopkeepers. Given that it's a bunch of magazine companies trying to convince stores to sell more magazines, I think that figure may be a tad high

Even so, we'll round to 50% on some other charges (getting the magazines printed + to stores).
On the digital front, you have development costs for a native application, bandwidth charges/digital content production charges (customers of digital versions expect more interactivity). You do get some money back on ads.
Apple has a couple other terms that are really not equitable in the view of the magazine industry.
- The limitations on the use of data are really untenable from the view of a magazine publisher. In an ideal world, we'd live in a world where magazine subscriptions were cheap, the content was great, there were no ads, and companies didn't sell our data.
Unfortunately, people want cheap magazines with great content. Advertisers want to know they're advertising to their target market. This means you need to know the demographics of who is buying your magazine - else you'll end up with low budget scattershot advertising. Even without the advertising money, the plain and simple fact is that the fact that you read such and such magazine is worth money!
I'm not too bothered that some companies know I read Wired & PC Mag. I opted out with the Direct Mail Association a while back and get almost no junk. From any other standpoints I don't see where that information is valuable...
- The lowest price through in app purchase/forced use of in app purchase is really crappy. For most people, an Apple ID is made through iTunes, which asks for iTunes immediately (at least, when I made mine through iTunes, I was forced to add a credit card to proceed - I wasn't even making a purchase at that time). Most people will have credit cards associated. In app purchases or lowest price would be fine, but the combination of the two means magazine publishers must charge everyone unfairly (e.g. bloat all minimum subscription charges to account for Apple's margins), or they have to stop using an app on iOS.
I
suspect Apple may back down on this, just like how Apple resisted $1.29 song pricing (on popular songs) for a while before eventually caving. The magazine/paper/book industry does not want to submit to Apple; people will get their content in ways outside of Apple's app store. It's essentially a game of chicken at this point.
I'll have to toy with my user agent and try the HTML5 app out...
So Apple does all the work of customer service, IT, HW servers, monthly data transfer, point of sale, and offer a hugh market of affluent consumers and they get only 10%? The magazine industry gives more than that to brick and mortar outlets and they have to make a print copy, where as iTunes' distribution is published quick and cheaper digitally.
Maybe you should rethink your logic! It's flawed
Your logic seems flawed from the perspective that subscriptions are typically $2 or less an issue, while in-store copies are at least $5 (that's for weekly magazines like TIME from what I've seen; most of the monthly magazines I'm interested in are at least $8/issue at the newsstands now).