Developing iOS apps isn't the be-all, end-all of programming. iOS itself is a consumption platform. It's garbage if you want to actually do anything (and so is Android), because the input bandwidth is severely limited. You don't need a command line on your phone, because there's hardly much you can do with it anyway.
But sit in front of a device with a keyboard - one that's meant for creative use - and suddenly, the command line shines as a force multiplier.
None of that is relevant. iOS is a fully-fledged OS, with at least as much complexity as anything else you'd be programming for.
Yet, to program for it, you don't need to use the command line. You just never need to touch it. It is possible to make a fully productive programming environment where the command line is not necessary, if you just put the effort in to do it like Apple has.
But sit in front of a device with a keyboard - one that's meant for creative use - and suddenly, the command line shines as a force multiplier.