The 'Bum's described are between the knees, and the waist, not Hobos. Standard sizes designed to suit the average, and actually fit few people doesn't take into account the different stages of growth, and the range of sizes in a school through different grade classes. Standard seats also fail to take into account, the different postures adopted during different types of study

Yes, I agree. I don't think adults not in school would want to sit in those chairs. The worst offenders are the deskchair combination. You can't move the chair away from the desk, and they are clumsy. We treat our kids very poorly, and it shows up in later health problems. Plus, it makes them hate to sit through school.

When I was teaching, the boss said he was going to spend the school's furniture allocation on ergonomic chairs; and the teachers each received a new chair.
Just like seat belts in buses, they cost too much; (and if parents cared about their kids they wouldn't send them to that school on this bus. They would be rich enough to look at alternatives.)

Being an adult one could argue that they had indeed had there turn in sitting in "Those" chairs, but of course with that attitude we would still be living in caves.

There are plenty of chairs out there that are designed specifically to counteract this kind of problem. all you have to do is go out and buy them.

I guess at the end of the day it will be "money" that dictates whether anything is ever done, and that of course will vary from school to school, state to state, country to country.