Its quite a lot to pay just to make a gamejam game available though, and that is where indie developers starts out. If you can't publish your toys without paying 100 dollars then it is a huge issue for onboarding new developers who just want to test what it is like.
The $100/yr is to publish to the App Store, which I don't think is the place for a gamejam game. You can download Xcode for free and distribute the resulting binaries for free.