Galaxy @1438
Agree with your point. Intermittent failure in a radio feed is not at all uncommon in my experience. Especially when the antenna elements, power divider, and feed system operates in an environment with high temperature differentials and vibration. Which is why the sole burden for detection should probably not fall upon aircrew.
And by 'self test' I did not mean to imply only a start up or power on logic test. The technology has existed for years to detect VSWR faults in the antenna, feed, or connectors while the system is active. Again I hope the final report sheds light on the fault management regime and engineering decisions behind it.