The best proof for me is that none of the top VR headset makers are using a wireless connection for their room sized demonstrations, despite the publicity stunt that would prove to be if they did, if only clumsily. Which also suggests it's more of a technical problem then a pure cost issue.
As far as those technical limitations go, it might work better for a shorter ranged front facing seated experience then the full 360° walking experience at first. So maybe there's still reason to hope for that.
BTW, would it be possible to use non-line of sight, electromagnetic waves to do something like 'Lighthouse' to triangulate position in 3D space... It's probably very specific to coherent light / laser tech, but I'm wondering if something similar could be achieved without relying on line of sight tech. Kinda the difference between radio and infrared wireless audio headsets I suppose 🙂
Limited CPU/GPU power is the main issue. Positional tracking via camera and target object is possible, but would be a potential tremendous drain on the battery and overheat the device? (Perhaps a way to have the camera in low power mode?)
Streaming on PC has to an extent been done already (Trinus VR) but latency again is an issue with wireless streaming from PC to Phone.