If you don't want junk food, you can enjoy simple healthy meals at home for cheaper than delivery. Even if you get your groceries delivered. But people like junk food
In addition, I often see people propagate the myth that eating healthy costs more, which couldn't be further from the truth.
The reality is that meal preparation and home cooked meals from basic ingredients are some of the healthiest things people can eat, assuming they understand basic concepts such as macro-nutrients and how they relate to body composition.