I think what extra money buys you is more variety in months which are lean for locally grown fresh produce.
So strawberries / out of season green beans are no healthier than swede / turnip / winter cabbage, but being able to buy out of season produce does allow greater variety of foods - or perhaps greater variety of 'mainstream' foods, because any allotment / veg garden grower will tell you that what is sold in supermarkets is a tiny proportion of the variety of edible vegetables.
Also, spending money on 'a hunk of animal protein' is simpler - but no healthier - than assembling a day's protein requirements from a wide variety of animal and vegetable and dairy sources. The latter is often cheaper, but balancing the overall meal (in terms of fat, carbohydrate etc) as well as getting the right amount of protein, requires some cooking and planning skill.
So those of us who eat seasonal local veg, rather than imported fruit, and assemble protein requirements from different sources, rather than buying it in the form of a single hunk of meat, do eat equally healthily, just more cheaply and differently, from the OP.
i also find the suggestion that 'spreading' protein from e.g. chicken across more than 1 or 2 meals means '4 days of bland food'. The OP's diet sounds impossibly dull to me, because it is in the sauces and seasoning and addition of a wide variety of different ingredients to stews, casseroles, pasta sauces, stir fries, curries, tagines, kebabs, pies, risottos etc which to me is the essence of my cooking - not grilling a hunk of bland protein.
I am also puzzled by 'protein is better food than carbohydrate'. if you eat the recommended amount of each per day, with no excess, then you have the right amount of protein and the right amount of calories - job done. if you choose to eat 'excess calories' - ie more than you need - in the form of protein because it is excreted more readily, then more fool you for cooking and eating excess calories.