I think you mean macOS not iOS, right? The problem is macOS doesn't lend itself to the tablet form factor. Software-wise, the macOS software ecosystem is not optimized for touch, and dual boot is a non-ideal, very un-Apple UX (Boot Camp was a necessary evil for them at the time). And hardware-wise, the thermal envelope for iPads is smaller than clamshells, so macOS would likely have to run slower or more limited than what users are accustomed to.
What I would like is macOS on a convertible laptop form factor with stylus input, no touch. Ideally a form factor something like the Surface Laptop Studio (which I use):