Actually it would hurt their iOS market greatly. iOS devices are worthless without their third party apps. And these apps can only be produced on a Mac. In fact, I bought my Mac so that I could build iOS apps. If not for 3rd party apps, it would simply boil down to the device, the software that Apple ships with and the browser. Android devices will clearly win hands down in such a scenario. Initially it would be the case of worse is better but over time it would overtake iOS devices in terms of features and sales.