We haven't had phones running laptop-grade CPUs/GPUs for that long, and that is a very real hardware feat. Likewise, nobody would've said running a 400b LLM on a low-end laptop was feasible, and that is very much a software triumph.
We've had solid CPUs for a while, but GPUs have lagged behind (and they're the ones that matter for this particular application). iPhones still lead by a comfortable margin on this front, but have historically been pretty limited on the IO front (only supported USB2 speeds until recently).
The GPUs are perfectly solid. Cheap Android handsets have shipped with Vulkan compliance for almost a decade now; the GPUs are equally-featured to consoles and PCs. The same goes for Apple handsets that run byte-identical Metal Compute Shaders to the Mac. For desktop use they are perfectly amenable. The hardware lacks nothing required for inference or gaming that dGPUs ordinarily support.
And even if you raise the requirements, we still have to contend with cheap CUDA-capable GPUs like the one in the ($300!!!) Nintendo Switch, or the Jetson SOCs. The mobile market has had tons of high-speed/low-power options for a very long time now.
The iPhone 17 Pro launched 8 months ago with 50% more RAM and about double the inference performance of the previous iPhone Pro (also 10x prompt processing speed).
They didn't make special purpose hardware to run a model. They crafted a large model so that it could run on consumer hardware (a phone).