[a1xndr]

Doing this is a huge amount of engineering work. Things like the usb controller, modem, audio, touch sensor, and many many more are often custom hardware without any specs available that you somehow need to simulate. That's not even getting into the display tech. And these things change with each new hardware iteration. In the OP repo, there appear to be 25 of these things that the author had to reverse engineer an emulate. And that's for 15 year old hardware. Things like usb controllers require thousands of lines of dense C code. Then you have all of the CPU extensions leveraged by iPhones that generally have poor/nonexistent emulation support. This type of emulation/rehosting is a notoriously hard problem even for simpler devices like routers. Modern game emulators typically move up the stack and intercept high-level graphics etc APIs because emulating all of the hardware would be a ton of work (and doing so in performantly would be impossible). The simulator that comes with xcode works in a similar way. But by doing this, you lose a lot of the capabilities that you might want from an emulated device (kernel/driver debugging, etc).

There is a reason that Corellium can charge so much for SASS access to recent-model emulated iPhones.