in practice such an event hasn't occurred within living memory.
Well, except for that one time two days ago when all their second factor stuff died for a very extended period... But other than that! Oh yeah and that one time a few days before where the entirety of office365's outlook email service died for 4 hours.. But other than that!
To be fair though presumably one can authenticate the old fashioned way still..
Biting the hand that feeds IT
