Quick summary
Apple isn't just demanding 30% for new business -- the subscription model is supposed to be an ongoing 30% for renewals.
Consider that an average magazine costs about £5 in a newsagent. The same magazine is often about half price when delivered as part of a subscription. The subscription is advertised in the magazine that you buy in the newsagent.
Now, the in-app purchasing guideline say that:
a) You're not allowed to offer the same service cheaper elsewhere (so that 30% comes out of your bottom line)
b) You're not allowed to encourage users to shift to using alternative subscription methods.
If Apple is a retailer, it's like telling magazines that subscriptions have to be the same as the cover price, and don't publish ads for your own subscriptions in the mag.
But in the world of IAP, Apple is *not* a retailer. The purchaser doesn't go to Apple real-estate, but simply connects to an Apple payment system. Visa, Paypal, Western Union, whoever... no other legitimate company demands such a high cut on what is essentially a cash transfer. *That's* the 1-2% comparitor: transaction handling fees.
Apple's problem is that they're not demanding cash when they deliver the app. If they made a distinction between truly-free apps (hobbyist produced vanity publishing) and free-with-strings-attached apps (including both commercially-sponsored advertising apps and free clients for subscription-based services), then they could charge a delivery cost for the latter, and that would be all fair and good.
But right now, Apple are happily giving away free ring binders and demanding a 30% cut of all paper that goes into it at a later date.