Compared to the rest of the school system, the price of a kid's lunch is a small amount of money, and it's certainly not worth the overhead of bookkeeping, administration, payment processing, and checking eligibility for each individual kid.
Take Finland as an example. Schools are paid for by taxpayers, costing around 8,000 euros per student per year [1] (the numbers don't change much regardless of which level of education you look at). Of that just 570 euro pay for balanced and healthy meals (mostly labor costs).[2] That works out to roughly 3 euro per meal.
The benefit of a good meal probably outweigh many other things you could do with that money when it comes to educating children that are your future taxpayers.
Take Finland as an example. Schools are paid for by taxpayers, costing around 8,000 euros per student per year [1] (the numbers don't change much regardless of which level of education you look at). Of that just 570 euro pay for balanced and healthy meals (mostly labor costs).[2] That works out to roughly 3 euro per meal.
The benefit of a good meal probably outweigh many other things you could do with that money when it comes to educating children that are your future taxpayers.
[1] https://www.statista.com/statistics/1134054/finland-regular-... [2] https://www.schoolmealscoalition.org/sites/default/files/202...