COM and OLE, which is based on COM, have been a core part of the Windows shell since at least Windows 95/NT 4.0/IE 4.
You can see this in the registry where shell extensions are simply registered OLE Components, using OLE Activation to to register themselves as toolbars, folder views, context menus and additional commands in context menus.
If you are referring to drivers or core OS concepts at a lower level, you may be right, but DirectX and class drivers were already using COM in places before Vista.
COM is a standard vtable implementing a single core interface, called IUnknown which provides a method of reference counting as well as a way to look up implementaions of specific other interfaces from a given pointer. These interfaces dervive from that base, so they can always be cast as IUnknown.
The rest builds on this base.
source: Inside OLE and Inside Windows 95
https://books.google.com/books/about/Inside_OLE.html?id=adpw...
https://www.bookdepository.com/Inside-Windows-95-Deluxe-Edit...
Edit: saw the reply below, the specific Longhorn components only expanded the scope of what is extensible to include searchable/virtual/indexed filesystem extensions and few other places, based on the innovative concepts in Longhorn. My reading of your comment originally was that Vista was a departure from what came before, though it appears that it may have been intended to say it was more of a return to the simpler COM.