V1 never actually shipped with any version of Windows
Windows 7 shipped with V2, 8 with V3, 8.1 with v4, and 10 with v5 and later 5.1.
5.1 is the latest (and last) version of Windows PowerShell.
All versions after that are just PowerShell (or PowerShell Core for version 6)
Not sure why they don't bundle it by default, but starting at v7.2 it can be updated by Windows update
I'll probably give it a spin anyway, might be I find some benefit and it looks like an interesting project. Being Rust based instead of C# .NET based could theoretically make it a lot faster (though I've not really had an issue of speed in PowerShell)