Daniel
In response to your question of "And yes, we hop into a new plane and we are thrilled by knowing how it can activate retard mode by RA indication. Ok that is cool, but what if the RA fails? What is the backup for this system if it fails and what is the backup for the other systems if this same system fails".
There are also two pilots to fit into the "system". Surely they are the primary means of controlling the aircraft, whether by monitoring the automation to ensure it is working correctly, or flying the aircraft manually.
Do you want backup systems to your backup systems, that aren't actually backup systems but aids to the pilot?