Well, processed foods might not reduce wall clock time, but because (as you mentioned) they remove the hands-on phase, it doesn't require the attention / human

Well, processed foods might not reduce wall clock time, but because (as you mentioned) they remove the hands-on phase, it doesn't require the attention / human time. Surely if you pop a TV dinner into the microwave, you don't stare at the microwave for the next five minutes, waiting for your dinner to finish cooking? There's also a secondary explanation that not everyone has access to a stove / hot plate and pots + pans (college students are a particularly salient example of this, especially when living in dorms). You could also attribute part of the preference for easy-to-prepare foods to lack of know-how (or even just perceived difficulty of prep) -- you'd be surprised how many people don't know how to do something as simple as fry an egg.