Streaming a game over the Internet is not comparable to streaming a game to a PC in the same room using a dedicated connection between a the headset and PC, where the antennas and radios on both sides are dedicated to the streaming video.
This is not something new. This is something that has been in widespread use for years, working quite well in existing headsets, like Oculus Air Link, Virtual Desktop, Steam Link, etc. The largest complaints about these solutions was often not latency, but image quality. This is what Valve aims to fix with foveated streaming, and all the hands-on coverage that we've seen so far indicates that it works extremely well. Valve is claiming 1-2ms of latency for a current-gen GPU, and 3-4ms of latency for an older GPU. Frames don't pass instantly over a DisplayPort cable either. You can't race the beam on a low-persistence display, you need to wait for the entire frame to transfer over.
Wireless is subject to interference, but 6 GHz is a very large and not widely used part of the spectrum, and interference doesn't cause a disconnection, it causes errors in the data or dropped packets. You don't wait for retransmissions, you just keep going and handle any missing or corrupted data through error correction or error resiliency. If a dropped packet causes a slight loss of detail in a small part of the frame for 1/120th of a second, you may not even notice.