I think the point is that if you the median American and you value your non-working time at your hourly wage of $27/hr then you're better off not spending, say 4hr a week, cooking/meal-prepping since you can get a months worth of food for way less than $432.
You should really only cook your own meals if:
* You enjoy it.
* You value/need your money more than your time.
* It's difficult to meet your dietary goals with purchased food.
My costs are less than 200 a month cooking for myself and family (buy in bulk friends), also I spend time with my family, listen to podcasts and clean while cooking, so directly assigning my wage to the cost per hour of cooking does not tell the whole story.
Another factor is health. Maybe in a large city is there is healthy, cost effective take-out but where I live the options are pizza and Chinese food after 8pm.
Is it really true that you can have all your food cooked for you and delivered to you at less than $432/mo in the US? I haven't lived there for a long time but that's only $14.40 per day which sounds like a pretty restrictive budget.
Note that families also benefit from economies of scale when cooking (buy ingredients in bulk and assign the work to the lowest income earner).
You should really only cook your own meals if:
* You enjoy it.
* You value/need your money more than your time.
* It's difficult to meet your dietary goals with purchased food.