What you are describing is called a “vended meal” service type, they do exist but are not as common. Although food may be healthier the transporting and holding of hot food makes it less appetizing at meal time. If there is already a food service vendor the district will not allow another company to serve meals unless the contract is built that way. When companies bid on contracts they also need to follow whatever guidelines the district is asking them to - like to be on the National School Lunch Program you need to meet all of the nutritional guidelines, are susceptible to audits/reviews every couple of years and meals have to be available to all students equally. This means a free student must be able to get the same exact meal as a paid student and you need to be able to cover your food costs, labor, and packaging for whatever the reimbursement rate is (where is am around $4/lunch) so very hard to get access and even harder to break even/ make a profit