There is very little that students can't study at home given at least some parental support. However, it's pretty clear that a significant number of students have basically given up on the school year.

Some of them have essential workers as parents and are left unsupervised during the day.

Some have parents ill equipped to assist them with school work those parents never completed themselves. (Hell, I went to college, and my kids' math work is a challenge.)

Some have no access to internet.

I saw an article the other day (I'm unfortunately having trouble Googling it up) that said some school districts have 15-20% students they still haven't managed to connect to teachers yet.

My son's school started remote classes this week. More than a third are missing in action. Naturally it is the third that benefited the most from the structure and support of school.

TL/DR - Students in poverty lose more ground when not in school than other students. Having an extra three months at home will exacerbate this.

In the US we have a school system where the children are off from school for about ten weeks in the summer. Educators have tested the children at the beginning of the school year and at the end of the school year to study the effect of this.

Students with decent to above average socioeconomic factors tested at about the same level from the end of the year to the beginning of the next.

Students with poor socioeconomic factors tested measurably worse at the beginning of the next school year compared to the end of the previous year.

They also looked at the delta from the beginning of the school year to the end of the school year. There was no significant difference in outcomes when socioeconomic status was taken into account.

https://journals.sagepub.com/doi/abs/10.1177/000312240707200...

Lets be honest. Many people just aren't cut out to teach many subjects, and a lot of people just didn't pass many high school subjects, let alone have a good enough understanding to teach them

I have several kids at home, all at different elementary grade levels and it’s not at all easy to keep them on track, motivated, and actually learning something while trying to get work done myself. The kids have been cooped up and its hard to keep the kids from bickering. Schools are not helping. They are giving assignments but telling kids things won’t be graded or are optional, etc... so kids don’t want to do some things. We have to undo that and push them to do it.

Given how competitive our society has become I am terrified that we will get behind.

I wonder why we have collectively decided to make society so competitive. We have more technology and resources at our disposal than ever before. We could make things easier on ourselves not harder. What’s the point? (I don’t believe all the competition and thrashing about is improving performance. Did stack ranking improve performance at Microsoft?)

English & Language Arts, including writing. Even for competent parents, unless you fully understand the curriculum and know how to teach it, providing direct instruction or enabling self-teaching in these areas is FAR harder than for math & science ... until you get into lab sciences where access to materials becomes problematic.

Not being in bone-crushing poverty with parents that are unable to help them.