Apple created this ecosystem and if we don't like it we can develop for any of the Android flavors and even Windows Phone.
The costs of the iOS and Mac developer programs are to keep Apple from losing money while they do all the heavy lifting for us developers.
Thanks to Apple I don't have to process credit card transactions, set up an app download system, handle refunds nor calculate the taxes to pay to the government.
For 30% of the revenue I'd consider that fair. I make so much more from sales that $99 + 30% is nothing if it lets me concentrate on what I love: developing apps!
I also used to develop J2ME games for a Japanese content aggregator back in 2005 and they took 69% of my earnings for providing the same services Apple does. I'm not being "robbed".
I'm curious, what's with the sense of entitlement? Do you really expect companies to offer these services for free? If not, what would be your idea of a fair price?