The world IT Pros live in is messy. Legacy systems that never got upgraded, new systems built as if history doesn't exist, and standards with spotty coverage at best. Also, Microsoft has a long, distinguished history of abandoning technologies after getting people completely committed to them - VBScript, Silverlight, Zune, take your pick.
PowerShell’s architecture was designed from day one for third-party extensibility, so that even if we got killed, you could keep going. This talk details those mechanisms.