Just look at modern public schools:
Standing in line
Walking in line
Yes; this is for the children's safety. We walk in a line out to the playground, for example, so that the kids don't run out into the street. It's the same as a parent holding a child's hand, except that a teacher does not have enough hands.
Going through a line of the mess hall/cafeteria to eat
Yeah, I never do this at a fast food place or kiosk. Ever. This skill is totally inapplicable to adult life.
Layout of schools is often long corridors w/ smaller offshoots, windows are very rare, giving it a prison-like feel
Depends on the architecture. Our school has lots of windows and a nice, bright feel.
Classes in most schools are larger w/ 20-30 kids, with all kids of the same grades taking the same classes (mostly)
Not in junior high/high school. Younger children cannot handle choosing their own classes, but the kids eventually get to pick what they want to learn, when they can make a responsible choice.
Same tests are given to every kid despite background
Not true at all. You just think we were giving the same test.
Learning is often based on ability to produce work based on pre-determined tests/worksheets, often standardized with set answers
Really? Your teachers did this, and weren't fired for incompetency? You should get down to your school board right away.
Truancy & late arrivals are punished
Yeah, once they get out into the working world they'll find out that a boss loves people who skip work and are constantly late.
"Bad" kids are sent to ISS (or OSS if severe), often a smaller room w/o windows where other like-kids are packed
No, these are not bad kids, but kids who have done something dangerous to others. Big difference.
School offices are often isolated from students & classrooms w/o the ability of students to interact with officials (unless they leave their offices).
Again, depends on the architecture of the school. Our offices are at the junction of our two main corridors, adjacent to one classroom and across the corridor from two others. All the kids pass by the offices at least once per day, and my counselor and principal are out to greet them during every change of period (except that they will not interrupt a meeting with a student to do so).
Virtually no breaks save for the standard 15-30 minute lunch in the middle of the day
Depends on the teacher. The current trend is toward mini-lessons of no more than 15 minutes, and time to get up/stretch in the middle of each period (several times if the school uses block scheduling).
Schools are very similar to, and IMO, were tailored to preparing children for the workforce, that is, entering an industry-based economy.
Should we not prepare children for the workforce? The number of families with two working parents has been on the rise for quite some time, and it's extremely likely that all of our children will be employed at least some time in their lives.