From a US perspective at least, you are right but also wrong. Like yes, it's cheaper to buy raw potatoes and dried beans and cook healthy food vs. ultra-processed "junk food." However, when most people attempt to eat healthy they do not opt for dried beans and potatoes every day. There is a huge time cost to preparing those ingredients.
And anecdotally, when I am eating healthier I am opting for a larger range of ingredients. Probably to keep my mouth interested as I am not getting the food that's been engineered to be perfect to my palate. While potatoes and beans are in my diet, I am also opting for a lot of vegetables that are more expensive, paying more for fresh herbs and interesting spices. I am almost always buying canned beans, sauces, and other foods with some processing to speed up prep time.
I think your analysis suffers from comparing processed food engineered to taste great to the blandest, driest raw ingredients. Factoring in the time and secondary ingredients to make those raw ingredients taste great adds a lot of cost. Add in the cost of more varied ingredients bc very few people want to eat beans, potatoes, rice, and bland chicken every day. And further, you're missing the savings processed foods add by being shelf stable. They can sit on a shelf or in a freezer for months or years vs. fresh produce with a much shorter lifespan.
So yes you can eat very cheap and very healthy, the vast majority of people will loathe that life over time. You can eat kind of cheap, very healthy, with a limited number of ingredients and have things taste great if you have a LOT of time to devote to cooking, this will still not satisfy many.
I just want to clarify that I'm obviously not suggesting to eat 3500 calories of beans daily, and that's it. Just like I did not straw-man OP by claiming he was arguing that we should live on 100% doritos.
I just made a simple comparison between two food types, on the one had the example OP gave (doritos), and on the other hand the most common staple foods eaten in the world, like grains and legumes.
Again if I have to repeat that, the most common staple foods in the world.
That I hope does enough to dissuade you from making the argument that eating these ingredients is a ridiculous endeavor. It's actually what the majority of healthy humans eat on this planet for centuries, the standard, the norm.
It's for anyone obese to figure out why they don't apply this norm.
Take legumes for example, cooked as a Daal it is eaten by more than a billion people all the time. 20 to 30 different types of pulses are cooked, and hundreds of recipies exist. If you walk into your local Indian restaurant, you'll experience a wide range of intense flavors. To say these are the blandest ingredients is incorrect, virtually everyone would prefer to eat such food daily compared to doritos for breakfast, lunch and dinner.
The idea that ultra-processed foods are a staple in my diet, is insanity. I'd be disgusted. I love ultra-processed foods as an occasional snack, not as a diet. My diet is healthy, affordable and tasty. Google and youtube are full of examples of affordable, tasty meals.
Minimal processing is completely fine by the way. There's little wrong with a good canned bean for example, great shelf life, minimal salt, maximal convenience, good nutrition, good price. Thrown into a salad with a simple dressing of olive oil and lemon juice, with some cut vegetables, gives a complete meal. Not more expensive than doritos, healthy, full of vitamins, calories, low glycemic index, protein, and 'cooking' is a matter of throwing the ingredients in a bowl and mixing, childs' play.
Same with the daals I mentioned, mostly a matter of throwing ingredients into a pot. Cooks itself with no supervision in less than half an hour while you're on your phone. Stores 5 days in the fridge or months in the freezer. Can be a great breakfast or dinner multiple times a week.
There's just tons of these options that are delicious and easy, cheap and quick, enjoyed by billions. Obese people just need better education and mentorship in my opinion. I could never be fat because my parents and environment showed me normal food culture, without it I'd probably be fat. I truly believe in the power of mentorship here, which isn't properly institutionalised or commercialised, which is why so many people lack it.
And anecdotally, when I am eating healthier I am opting for a larger range of ingredients. Probably to keep my mouth interested as I am not getting the food that's been engineered to be perfect to my palate. While potatoes and beans are in my diet, I am also opting for a lot of vegetables that are more expensive, paying more for fresh herbs and interesting spices. I am almost always buying canned beans, sauces, and other foods with some processing to speed up prep time.
I think your analysis suffers from comparing processed food engineered to taste great to the blandest, driest raw ingredients. Factoring in the time and secondary ingredients to make those raw ingredients taste great adds a lot of cost. Add in the cost of more varied ingredients bc very few people want to eat beans, potatoes, rice, and bland chicken every day. And further, you're missing the savings processed foods add by being shelf stable. They can sit on a shelf or in a freezer for months or years vs. fresh produce with a much shorter lifespan.
So yes you can eat very cheap and very healthy, the vast majority of people will loathe that life over time. You can eat kind of cheap, very healthy, with a limited number of ingredients and have things taste great if you have a LOT of time to devote to cooking, this will still not satisfy many.