It’s hard to blame the school system for the failure of society at large. In order to open schools you needed to get a) transmission down to an extremely low level, b) have rapid testing results (like China), and c) have enough contact tracers to track down contacts. In the northeast we’ve mostly succeeded at A, and in some places (MA, DC, VT, NY) at C but not really at B. You really need to have all 3 to open up safely.