No one is asking for a 50GB ISO. ISO is another way of saying "a single file". If you could provide a single ZIP file with SHA or MD5 hash we are happy too. Look at Xcode - the main bundle is around 3GB and all the SDKs, simulators, and documents are available as in-app downloads. Or you can look at Android Studio, or Eclipse. The base software package is relative small and there are options to download plugins/components.