School lunch programs across the world get setup and perpetuated for a variety of reasons. They also have a variety of funding models.

For the US specifically, major federal programs began during the Great Depression as a two for one combo. It solved the direct problem of... people being poor and their kids not having food/lunch, and it also provided a reasonable supply sink for the government to buy out supply from farmers to help keep things going.

Anyhow, since then for a variety of reasons, subsidized/free lunches have stuck around. Primarily because the underlying problem (food insecurity) has not been adequately solved. School lunches also tends to be amongst the more politically palatable/defensible forms of welfare in the United States, since its very structure and beneficiaries make it harder to criticize.

So while expansion of SNAP or other programs that might help tackle general food insecurity might run into headwinds, most of those arguments tend to falter when it comes to feeding children directly at school. For example, it's hard to argue that getting free lunches at school would encourage "abuse and malaise" amongst students. Similarly, since the composition of lunches tend to be under control of the supplying organization, there's reduced concern of people spending their assistance on "luxuries".

Do you mean you always have to bring your lunch to school with you, in Australia?

I went to a weird high school in the US where that was the case. They just didn't have a lunch room, so everybody sat in the hallways at lunch time. But yeah, all the other schools I've heard of provide lunch. Most offer breakfast as well, as an option.

The US has discovered that there's a substantial portion of the population (which for this could be 1%, 10%, 20% whatever) who is really bad at raising kids, basically. If the school doesn't provide lunch, the kids would simply not eat any lunch. So they provide lunches, because it's easier than handling the fallout from some kids not eating, etc.

As a child I never had "provided lunch" but I also went to private school; we didn't even have any option through elementary (grade 8, about 12). High school had a greasy burger joint (think: high school football game concession stand) but that was it.

Providing lunches involves enough work that providing breakfast, too isn't much more expensive.

(The programs may have started for other reasons but the above is usually why they continue. It's also hard to stop doing something like "provide kids food" once you start.)

Nutrition is an important precursor to education. It saves time and effort of the parents providing individual lunches, as well as guaranteeing a certain minimum level. There's always a few kids whose education is impacted because they're not well fed, due to poverty or chaos at home.

at what time do kids in australia come home from school? for comparison in germany the average school day is 4-6 hours, depending on age. in the US it is 6-8 hours. in germany kids usually come home for lunch. in the US they usually don't. those two hours make a big difference in what kind of food the kids need to bring to school. in germany a snack is enough. that's easy for parents to accomplish. kids in the US need a real meal for their lunch break in school. but cooking food in the morning that kids can carry and eat 5 hours later? even wealthy parents don't have time for that.

If the government forces you to be someplace, under threat of imprisonment for your parents, then they'd better at least feed you.