lisa,
just like in many things today, i think people just began to go for convenience. i recall as a kid that one of my friends always ate tv dinners. i used to think he was so lucky - they seemed really cool. he was always the nervous, fidgety type. i now wonder if much of his demeanor was caused by this food.
i was lucky that my parents, especially my dad, limited the amount of junk we could eat. i remember that for every bowl of frosted flakes we ate, we had to match it with one of grape nuts or total. he started buying mostly brown bread, instead of the white wonder bread, etc.