I tried overnight oats once. They were vile. And cold.
never heard of chia pudding before but it looks interesting I might try it. Not as a breakfast though. My breakfast is fruit juice, yoghurt, then about a pint of decaf coffee and toast.
more generally, I used to be a teacher.
as a school we had in breakfast bars because quite frequently kids would turn up in school not having had breakfast and they’d be hungry.
some years depending on what classes I had I used to bring in a pack of carrots and give them out in the first lesson as so many kids would be hungry and not have had breakfast at all. (Carrots was about the cheapest fruit or veg I could find that didn’t go off completely in the week).
some parents are living in temporary accommodation that has no cooking facilities at all. None. So they aren’t going to be doing scrambled eggs or anything like that.
the food bank near me is very careful what they give out in terms of expecting people to cook stuff as access to ovens/microwaves etc is difficult. Most people do have access to hobs but ovens can be expensive to run (especially if you are doing something like jacket spuds which need a long time).
sure, onions carrots and lentils are cheap. And when I was a student I pretty much lived off vegetable stews and chillis. But they aren’t the sort of meals that appeal to kids very much. Or adults frankly.