"Inconvenient radio transmissions."
Well, maybe they just had a REALLY short window when they were actually using unshielded transmissions before moving to tight point-to-point?
Or their homeworld has an atmosphere that effectively absorbs/reflects/distorts radio.
Or their is a nearby stellar object that is emitting over the easiest to make frequencies, so radio-tech was stillborn.
Or their atmosphere/environment made other alternatives easier/cheaper/more effective in the short term.
Well, maybe they just had a REALLY short window when they were actually using unshielded transmissions before moving to tight point-to-point?
Or their homeworld has an atmosphere that effectively absorbs/reflects/distorts radio.
Or their is a nearby stellar object that is emitting over the easiest to make frequencies, so radio-tech was stillborn.
Or their atmosphere/environment made other alternatives easier/cheaper/more effective in the short term.