I think the issue with McDicks prices is that they are staying ahead of the inflation curve while the rest of the restaurant industry is getting felted. You generally want a 25 to 30% margin on your items from just the base cost of it in order to stay ahead of labor and facility costs. So that you turn a profit. The problem for everyone is the price of Food has been skyrocketing and the consumer base is getting sticker shock. Its not just McDonalds. Five Guys is starting to eat shit too for their prices. As for the Independent stores can't keep up as their prices are more sticky then the big boys. Chic Fil A is able to thread the needle due to the fact chickens are dirt cheap and as Beef has skyrocketed in price producers have increased Chicken production to meet the new demand for Chicken. Chicken Meat is also more adaptable to scaling up which is why you've not seen eye watering price increases as compared to beef.
Its still retarded high though. A packet of Chicken thighs that cost 1.99 four years ago will now set you back 4.99.