How do you imagine the cross-platform administration of Windows and Linux, if they have completely different insides? Automatic driver installation in Windows and Linux are two different things.
Many things in windows networks are set centrally via a global policy about what Linux has no idea.
Again, install the software - it is different.
For Linux of course the best is bash
Windows - powershell/bat
You can put git on windows so that bash scripts worked.
But still, for a number of tasks, you will need the script to do conditional branches and call or sysinternals and powershell for windows, or gnu/bash sudo on Linux.
For banal things - bash/python/perl should be more than enough, but it's not so much automating administration as General automation.