Yes. And without over stating it, iOS is an amazingly robust, very secure OS. it has high trust and low trust models, a secure zone, special purpose hardware and an operating system designed around minimum access rights models which manages to keep going, despite app authors worst intentions.
At one level, it proves the model. The shame is that Mach otherwise has kind of not taken off. Gnu the OS was going to be Mach at the core, at one point IIRC
I'd have to disagree -- the lack of OS-level sandboxing primitives such as seccomp-bpf and SELinux[1] means that exploits happen rather regularly in iOS rather often ([2], among others).
iOS has a perfectly good sandboxing model that is literally called "the sandbox". You will note that the impact of that bug is limited to the process it is triggered in for precisely this reason.
iOS is without question one of the most secure OS out there today with any amount of real world use but the gap between what it is and what state of the art looks like is also insane. Fuchsia is actually quite well aligned with something that’s actually defendable in the real world and across time.
At one level, it proves the model. The shame is that Mach otherwise has kind of not taken off. Gnu the OS was going to be Mach at the core, at one point IIRC