Though iOS is, out of the box, more private than stock (non-AOSP) Android, nothing compares to a custom ROM. You can even debloat android and disable play services, if you don't want to risk bricking your device, or if there aren't any custom ROMs available.
Of course, the average Joe wouldn't do that, but I guess most people on HN are quite tech savvy.
I for one have built enough Linux kernels from scratch, and patched enough Linux drivers into working — thanks, so no one can call me an average Joe when it comes to tech. However, I mostly left all of that behind outside of work years ago, I’m desperate for time, not money, and I have way better things to do with my time than dick around with a custom android build, thanks. You do you, but Apple provides me with a ‘good enough’ service that saves me a lot of time.
Of course, the average Joe wouldn't do that, but I guess most people on HN are quite tech savvy.