No one. You are 100% correct. Our regulatory obsession with radio started with the AFIZ many decades ago.
As a " make jobs" for FSO's every aircraft within an AFIZ had to communicate with the FS ground station. Fly 15 miles away from Dubbo and you had to call them with a full position report.
Then we brought in mandatory radio and full postition reporting for VFR above 5000'.
Created lots of complexity and jobs and then ingrained on most of us that " fly by radio" was the only way we would stay alive.
We nearly fixed that with the introduction of NAS2b however after 3 months of no frequency boundaries on the charts and when it was just starting to work really well , Airservices undermined the whole change by sending out a chart with frequency boundaries.. they gave no education as they didn't even know how this half wound back system should work.
Since then it has been a stuff up!