He means in the sense that the automobile killed the horse.
And I agree, and was tweeting about exactly this yesterday. https://twitter.com/eric_wvgg/status/1207374861955469317
The problem isn’t that Google killed Reader, it’s that Reader got such traction to begin with. There were always better alternatives, and they’re still around and better than ever, but they aren’t doing anything to make RSS more accessible, user-friendly, or prevalent.