Some teachers CAN work from home (not PE, Home-Econ teachers, etc.), but it's a less-than-ideal situation.

Are children self-motivated enough to work from home? I know many adults who aren't. Without adults to keep children accountable a total work-from-home schooling is likely to create gaps in the kid's education. And which type of child is the least likely to have an adult around keeping them accountable? Impoverished children.

A counter argument is that keeping kids physically proximate often exposes them to violence which makes school a lot harder and tends to really mess people up.

Lots of modern jobs worth doing will end up remote (at least occasionally and often permanently) so it’s probably a good idea to start training them when they’re younger anyway.