It’s also not necessarily that simple. You need space to route the wires for the port… You could potentially do it, but you might not have space for cameras or speakers, for instance. I suspect something like this wouldn’t work for iPhones with Face ID for instance (though maybe you could push the port to the side a bit). It’s probably not worth the compromises for most people, especially since, let’s be honest, USB-C and lightning both suck for headphones anyway. It’s just not a good enough connection in my experience.