I think this is extremely shortsighted. If this were the whole story, then why would Google be going through the effort of integrating Wikipedia data into zero-click results? Out of charity?

No. Because big picture, those people who go to Google and leave without clicking anything had reinforced that Google finds everything they need easily. It makes them more likely to come back.

So Wikipedia does lose clicks to Google in the sense that it loses to Google an opportunity to impress its brand.

Side note. If you have Firefox I would suggest that you go on Wikipedia.org, right-click the search box, click "Add keyword to this search", and pick a keyword. This makes it faster to find information that you know is on Wikipedia.