A handful of student's expenditure covers a teacher's salary. Where does the expenditure for the other 25 kids in the class go?
There is a LOT of infrastructure. The schools have to be built, they have to be staffed(there is a fair bit of support staff, to keep the teachers in classrooms teaching).
From cafeteria workers and janitors to IT people and payroll, back office and grant people. High Schools might have a few thousand students that congregate there every single day, that's a small town. Our local high school's have a dedicated full-time HVAC person for instance, just to keep the insane temperatures outside from getting into the classrooms.
https://www.nycenet.edu/offices/d_chanc_oper/budget/dbor/sbe...
It just says:
Pct of Per
Pct of Public Student
Total Exp. School Amount
i. Teachers $10,124,379 32.1% 37.7% $9,914
2) Some kids with certain needs require one entire staff member with them at all times. There may be a few of these in a given school.
3) Somewhat more require something like 1/5-1/10 of one or (more often) two staff members’ time (think “special ed” rooms)
4) These figures may include serious outliers. Selective public schools often have very high per-pupil spending, and schools attached to correctional institutions sometimes register six figures of spending per student, to pick a couple examples.
TL;DR if we could suss out what’s actually spent on a “normal” student at a “normal” school, it would be way lower.
I bet if you go ask what those secretaries actually do during their day, you will find they are very busy doing lots of stuff that has nothing to do with the traditional "secretary" role. It was probably the only way to get it stuffed into the budget, so the actual work they do can get done.
Certainly some Administrators have actual secretaries that do traditional secretary duties, but they are few and far between in my experience. Most of the ones I've met do lots and lots of other things totally un-related.
As for multiple Asst Superintendents, that's totally normal, usually one is in charge of "back office" payroll, HR, the business end of things and another is in charge of education type things. At larger districts you might have 1/2 a dozen of them, all specializing in a particular area.