I can't say for sure but it was my impression that many of these students don't have parents at home during the day. The school system my gf works for is in an area with several meat processing plants, which I assume are considered essential. There are also many undocumented workers in that area. For those who were doing jobs that weren't considered essential, they probably can't rely on being able to collect unemployment and had to go find other work. It's a lot to ask of middle school age children to be self motivated especially if their friends around the neighborhood were outside playing or coming over to hangout, regardless of lockdown orders or not.