This fall may be the biggest moment of truth for public education since the 1970s. After seeing enrollment in government-run K-12 schools decline by 3 percent in COVID-marred 2020–21 (including 13 percent for kindergarten and pre-K), all while homeschooling tripled, the $122 billion question facing this new school year is whether that defection is an aberration or inflection point. Given the amount of time that families have now had to plan around school-opening policies that have been among the most cautious in the developed world, would they choose their neighborhood school, or seek alternative solutions with more predictable schedules? An early bellwether came clanging in…