The job of a teacher is a very difficult one.
Not only does a teacher has to engage into teaching mostly following the textbook.
It is very difficult and challenging to keep students engaged.
Children, who’s natural instinct is to talk, play and move around. Teacher is given the job to make them hold on to one place, for hours.
That becomes the main goal rather than learning itself.
If a teacher really wants all children to really learn and help them. Then it becomes an even more difficult and tiring job,
Learning happens best in small groups.