It actually is, as it provides scripting across the whole OS stack and applications, closer to Xerox, Lisp Machines and Smalltalk REPL, something that no UNIX has ever offered, with exception of outliers like NeXTSTEP and OS X.
This is all technically true, but the thesis is that PowerShell makes it all horribly clumsy to use.
From the perspective of the Lisp Machine or, hell, even the AS/400, PowerShell (and, while we're here, the CLR) doesn't quite go deeply enough, pervasively enough, across the system to make it truly useful in the same way.
Extremely clumsy, yes. And not idiomatic - a vanishingly small people learning PS will be able to usefully discover, use, or troubleshoot this utilization.
At the very least they could have helped with the discovery/usage problem, but that would probably have been a really tall order for one little language to do.
Not quite. What I'm more alluding to is something like, say, rewriting smss.exe and csrss.exe to be CLR programs (along with the implication of porting the CLR to the Native API) and giving PowerShell access to their internals directly.
