Most corpos and banks are basically built on Excel, Outlook, Teams, Sharepoint, etc.
If you pluck that out it completely freezes 50%+ of their operations, people really don't get how much stuff in modern companies is reliant on MS stuff (and thus why they are one of the richest companies on the globe)
Yes, but there are comparable alternatives. Sure, the transition requires resources and effort, but to the point of making a company bankrupt?
In some cases I would say yes if there was a hard limit (even few years) to migrate. Again, most people that didn't work in many really big corpos and banks don't comprehend how reliant those businesses are on the MS office stack.