I see you haven't met Google's production backbone network(s)... We intentionally didn't connect the Middle East and India (due to a combination of geopolitics and concerns around routing instability), so any traffic between the two would go the long way around the world, incurring a 200+ ms RTT penalty.
Agreed entirely on your point that if you're buying multiple redundant links, you're responsible for making sure that they're actually relying on different underlying fiber spans.
From there the worst that can happen generally is that the packets spiral the wrong way around the continent