I'll add that much of the concern is about social skills more than academic skills. Academics can be made up, for the most part, but there is a window of opportunity for many social skills. If young people miss those milestones, it can be very difficult to recover fully.
That's why many districts are focusing on how to get elementary school students back as soon as possible. There is somewhat less concern for high schoolers. (Middle school is its own animal; they likely fall closer to the younger ones as far as their social needs.)
Also there is a huge amount of concern for certain subgroups of students, such as those receiving special education services, those who are language learners, and others with specialized supports provided through the schools.
And then there are the children whose lives are in danger by being stuck at home all the time. For far too many students, school is the only escape from an abusive or otherwise dangerous situation. These students are at extremely high risk right now, and it is nearly impossible for those who care about them (teachers, counselors, etc) to ensure their welfare.
It is a terrible situation all around, and there is no one simple "right" answer.
would losing a single year of school be that terrible though?
