For private individuals and small institutions, yes, they would definitely use linux if windows was 100% impossible to pirate.
For corporations and bigger institutions, no, they would 100% continue to use windows just because of the control they can have on their devices, group policies, single sign on, and so on. It's possible to do that on Linux, but not as easily. They're already paying 15 dollars / month to microsoft just for AAD/entra/[whatever they call it this week] or even more to have office integrated with that and $200 for a permanent license for a single PC is a drop in the bucket