An excellent post I had forgotten about by JM Cecil detailing a method not described in that great (8 minute 
) vid, it involves setting up dummy buss inputs. From last July.
Tutorial: Routing VSTi back into an audio track - Cubase - Steinberg Forums .
If I’m reading some of that post right, at least one other DAW, Reaper, requires routing to get a VSTi to audio. I thought maybe Cubase couldn’t do a single-click kind of VSTi>>Audio because of some old legacy code, but Reaper being pretty new I guess shoots that idea down. Oh well, guess I can live without knowing why it has to be this way!