Yes, when Apple bought NeXT (I know, more like the other way around) they wanted the graphics model to follow something akin to NeXT's — which was based around Display Postscript. The modern equivalent was of course PDF.

If you could render into a PDF context with your graphics engine (CoreGraphics) you would have a near print-ready document. (You still need to pass along additional info regarding whether to print duplex, number of copies, etc.)

So anyway, Save to PDF, Open in Preview were basically free.