Is it? Every large company has a well compensated CTO whose job it is to think through these sorts of hypotheticals. But “nobody gets fired for choosing Microsoft”, and so the monopoly continues…
"A sound banker, alas, is not one who foresees danger and avoids it, but one who, when he is ruined, is ruined in a conventional and orthodox way along with his fellows, so that no one can really blame him"
The worst part is that very poor diversification / groupthink is exactly what creates financial bubbles and financial crises. We seem to be reaching that uncomfortable too-big-to-fail scale in computing / cyber security.
Other shoe will not drop because the liability for mishandling customer/user data is minimal. I don't expect a scenario where Microsoft (of even Microsoft's cloud division) folds after this. Bear Stearns actually collapsed after their fuckups.