These would not be restaurants. They would be food factories, and already exist. You can go into a grocery store and buy pre-packaged pre-made food from dozens or hundreds of different factories collected together for your convenience
The pre-packaged food in grocery stores has to be preserved somehow, perhaps most importantly with excess salt, which often makes it pretty unhealthy. Fresh made food also tastes better.
These would not be restaurants. They would be food factories, and already exist. You can go into a grocery store and buy pre-packaged pre-made food from dozens or hundreds of different factories collected together for your convenience
The pre-packaged food in grocery stores has to be preserved somehow, perhaps most importantly with excess salt, which often makes it pretty unhealthy. Fresh made food also tastes better.
In higher end grocery stores you can get lots of made fresh that day foods, even sushi and cooked dishes.