We are now nearly in the situation where most people have had it and the virus shows no signs of abating. This is not a bleak outlook simply a realistic one. You've either had it or are going to get it. The bleak outlook is the one that says you should cower alone and apart from friends and family until you do get it. Go get vaccinated and live as before.

Again, you aren't sacrificing the teacher's well being. The teacher is, anyway, most likely going to get covid. If a teacher doesn't like being exposed to children they should resign or be fired. Schools are not for the benefit of teachers but for the benefit of children.

Once vaccinated you are unlikely to require hospitalization. Actually, you're unlikely to require hospitalization regardless of vaccination but especially unlikely once vaccinated. Maybe it's sensible for people to make some minor changes to "flatten the curve" but going to remote school is no minor change and it is far worse than the negligible benefits.

While it's true you can catch the disease multiple times subsequent infections are less likely and less severe.