For everything else, like Windows, Office, Teams ,etc. That's easy.
But, every single business I worked at in the past 5+ years have been on Either MS Azure Cloud or AWS. Replacing cloud infra services is going to be very difficult. No other business has the level of sophistication these companies have. This could be a really big challenge.
Yes we could go back to on-prem hosting, but that means increased costs of all kinds. And we all know how much hardware costs these days.