I agree with you. You always have to test a program on every platform it's supposed to run on. However, the hurdles for doing it on Apple devices are a lot higher compared to everywhere else. For example, you don't need a Windows machine, all you need is a Windows license for ~100$ and you can install it on any computer. Similarly, you can run Android Studio on any computer and even though the Android emulator is pretty good, you might need a cheap ~100$ Android phone for some actual on device testing. But you cannot pick up a macOS license and install it on a virtual machine or another computer and Apple doesn't allow XCode to run on other operating systems. To say it bluntly, as a developer you are expected to make your programs available on multiple platforms including Apple, but Apple themselves don't make their software available on any other platform besides their own. If I could just install XCode on a Linux or Windows machine, it would be a lot more accessible. You probably would still need an iPhone for some final on device testing, which is still quite expensive, but not as expensive as having to buy two devices.