For perspective: I come from a country where “cafeteria” food at school is good and affordable (most is less than the equivalent of 5-10 USD max and it’s not slop, it’s actual food), but it’s not an obligation for everyone since it’s up to the student if they want to buy something or bring their own lunch.
The “cafeteria” in my school isn’t a typical American one, rather it’s closer to a canteen where they sell food you can purchase from cup noodles, fried stuff, sandwiches, baked goods, etc. also appliances like a kettle or microwave are available in the dining hall for students to heat up left overs if they wanted.
The thing I tend to notice from American schools (according to US movies, there’s bias whether it’s true or false) is that they tend to depict kids always heading for the cafeteria for recess or lunch picking up whats available instead of bringing their own food from home (left overs from dinner), why is that the case?
FWIW, in Portugal, during my youth, I ate at the cafeteria rather often. It was decent food for the most part (it was also my first exposure to soy minced meat). It was hot, didn’t involve carrying a lunchbox, and it was tasty and convenient and cheap. Eventually I opted to go back home because I lived close enough to walk, and mom’s food is better.
We did not get ways to heat up food (though I bet you could have asked the cafeteria staff if you needed it) of our own, though.