They can be disappointed. But if they're 'shocked' then they didn't do their research. In terms of backward compatibility, Nintendo did more than almost anyone for longer than anyone. Apart from the odd specific model, all their dedicated handhelds by them have always had at least one generation back full hardware backward compatibility, and their last two home consoles before the Switch also had full hardware backward compatibility.
Nintendo also re-released large numbers of previous generation games in many forms even well before the virtual console, in the form of extras (Metroid in Metroid Prime, NES games in Animal Crossing) dedicated budget releases (NES Classics on GBA), remakes/ports with extra features (eg SMB Deluxe on GBC, Mario World on GBA), Special releases (Zelda bonus disc) odd hardware add ons (Zelda remakes on Satellaview, NES games on e-reader).
And of course the original Wii Virtual Console itself, which had (still has, technically) something like 800 titles available in total from them and third parties on a large variety of legacy systems, which were transferrable to the Wii U and fully playable on it too. And finally the Mini consoles as a cheaper standalone bundle, and recently NES online as a subscription service bonus just started.
I'm guessing VC simply did not have good ROI in the end, and it's consumers who essentially closed it down. I don't have any proof but if it was a huge money spinner it would surely be alive and others would do it too. I don't think it's a coincidence Sony and Nintendo are essentially doing this the same way, market forces showed them both the direction.
The key in this thread isn't any of that though, it's the implicit (sometimes even explicit) next step people make, which is that they're at least pseudo-justified in pirating whatever they want because of that 'disappointment' you mention.
