The price of buying a computer to compile and ship the code with is not going to kill many business models that would otherwise have worked (you can buy a used Mac Mini or make a Hackintosh if you're feeling adventurous vs the TOS). But forcing you to use their payment system which takes a 30% cut - that can and does prevent business models from even being possible. If Apple were not allowed to enforce their payment system's monopoly and reject apps for even linking to other options (I don't get how that can be legal), but had to compete with other solutions, that 30% cut would almost certainly be less.