Your point of view here will depend somewhat on your level of success.
In the current model, the barrier to entry is pretty low. $99 gets you xcode, plus you need done hardware.
Once you've made something you need to reach a market. A good market place (like a regular super market) brings together suppliers and customers. That market has costs.
One model for costs is to charge each app the same amount. Say, for example $5000 per app submission. Lots of successful suppliers would like this model because it raises the bar for completion, and means they pay less money.
Another model is free-to-enter, but takes a cut of the sales. Successful products end up paying much much more than stuff no-one wants.
Overall I think I prefer the second model. Wildly successful apps, and developers, are basically funding an equal-access marketplace.
Now, of course there are winners and losers. From published numbers its clear most apps make 0,for some definition of 0. Every developer thinks their app is special, but most are, well, not.
Good marketing helps, buzz in the tech-press, visibility on forums, shows and events, and do on. Some do nothing, waiting for their big apple-lottery break of being "promoted in the app-store".
Developers risen in a world of cost-free-everything believe that they are the sole value-add in the path from hardware to consumer. Apple should provide this appstore connection to the developer free of charge. Of course developers think this, and they're welcome to think this, but it doesn't mean Apple has to do it this way.
Developers have choices. They can choose to develop for Android instead. They can choose to use the Google store, or a different store, or make their own store.
If you develop for iOS you know the rules. If you see value in that market (and you like the low barrier to entry) then go for it. If you make money then pay your 30%. If you don't (and the odds are you wont) then delight in the money you saved by there not being an entrance fee.
But don't sign up for the competition, win the game, _then_ complain the prize money is too low.
You may like Apple, you may not. But its your choice to join their game, or not. There's no bait-and-switch here, the rules are clear and well understood. You either accept their position of strength, their ability to crush you on a whim, their ability to arbtitarily create winners and losers, their ability to earn royalties on your code (on their platform) or you don't.