All very elementary
<<So, 411A, let's get this right. You have experienced GPS becoming unavailable - so it is NOT 100% reliable. But because it happened not to be at a critical phase of the flight - it's all right then. Aren't you the lucky one! What if it had occured at a critical phase of the flight?>>
What?
You have never heard of INS becomming unreliable?
I have had two out of three fitted failing more the once certainly, yet we pressed on with the flight, using other modes of navigation.
Just because 'it' might fail enroute, is no reason to get in a panic, now is it?
For approaches, there are VOR's and ILS's available, and indeed the odd diversion might be needed.
All in the name of the game of professional flying.
Now, I can understand why younger guys might have a slight 'problem' but those of us who have been around awhile, manage to cope.
Then we come to map shift on several types just a few short years ago.
Did these guys panic, and have a fit?
I suspect, surely not.