All that would resonate with me IF Terics were dying in such a way that they were causing people to have to end dives early. Or even to miss dives.
It's not like they don't work...
My first Teric had a black screen. That would have ended the dive if I didn't have a backup AI computer. It was repaired. The AI antenna went out. That would also have ended the dive without the backup. This was replaced.
My second Teric had a bad battery and was replaced. That was just a nuisance.
My third Teric had an antenna failure and was replaced. Again, would have ended the dive without backup.
My fourth Teric had a bad battery and was replaced, another nuisance.
My fifth Teric had a bad battery and was replaced, another nuisance
My sixth Teric flashed like the flashlight function before turning off. Neither Dive-Tronix nor Shearwater had seen this before and electively replaced it. I don't know if this would have affected performance I have not heard back from Shearwater yet regarding their diagnostics.
My seventh Teric just had an antenna failure and will be replaced when I return from a non-diving family vacation. This required a backup.
My eighth Teric will be perfect
So, at least 4 of 8 problems I have had required a backup not to have affected the dive.
Edit: Teric #7 was repaired rather than replaced, I'm still on seven.