This is entirely correct.
Buying decent fresh ingredients can be rather pricy and needs (ideally) to be done on the day, or maybe the day before (i.e. planning, time allocation, journey etc). Then you've got prep-time, this can be non-trivial, and then cooking, which can require multiple pans, maybe an oven on, boiling a kettle, all the washing up etc - this all takes (very expensive) energy as well as more time.
Also, not everyone knows how to cook with multiple raw/fresh ingredients, I've worked in a kitchen as a second chef (many years ago now!) so I know my way around this stuff and how to do it properly, how to prepare veggies and raw ingredients, meats etc. Many people do not, for whatever reason, they've simply never learned.
I like to knock up a decent meal for the family from nice fresh ingredients at the weekend, but I do it then because I have the time for it, time to do the shopping, time for the prep, time for the cooking, time for the clean up etc, and it's not cheap either, you could certainly get a bag of Iceland stuff for a lot cheaper, 'prepare' it a lot easier, quicker and cheaper (far less energy and hot water use), and everyone's still fed at the end of it.
We live in a country where people turn down raw stuff from food banks because they can't afford to cook it.
dunover's meal of chicken, potatoes and broccoli doesn't sound very appealing (and I don't know where he's getting those prices from), you're going to need herbs and spices, a bit more variety in the veg, what is the chicken being served with in terms of a sauce or whatever? It all adds up. And none of that stuff is cooking itself.