will it be a mass exodus to Linux/Mac?
Linux: Unlikely. Although Red Hat has recently been lobbying very emphatically, Linux for enterprise applications is still a wonder bag. Windows is reasonably stable as far as essential system functions are concerned, Linux, on the other hand, is a patchwork and this is noticeable even in RHEL and SLES.
macOS could well be an option. Apple tries to strictly follow the principle that user privacy plays an essential role (they converted me from Android to iOS with this), but I assume that macOS will also move "into the cloud" in the medium term (Service note: "The cloud" is just other people's computers.) as soon as Apple will have created a way to learn from the mistakes of others after years of watching the market. They always do.