> Finally, if there were a real clamor for meal kits, what's to keep Whole Foods or whoever from just assembling their own meal kits?

Pre-portioned, pre-prepped,low-cooking-effort packaged food products are already a big item in various forms for supermarkets. As are fully cooked meals. No doubt meal packs will be too, of they are popular.

OTOH, Grocery stores selling fully-cooked meals haven't killed restaurants (not even takeout-focussed restaurants).