The reason the schools don't pay, at least in Illinois, is because the taxes now fund a higher percentage of the school budget. Years ago, the state put in a much higher percentage of funding (most $$ came from the state funds). Now schools are expected to be basically self funding- through tax bases, etc. Same for higher education. Thus, although budgets have increased (inflation for salaries, paper supplies, building maintenance, in our district- a 5% increase in students PER YEAR!, special education costs as we have more children born each year with disabilities and requiring special interventions- and are we going to tell those kids they can't go to school like in the "old" days?) the state and federal $$ have decreased each year.... Now add the cost of the new No Child Left Behind regulations, and boom- there goes any idea of budgeting! Thus, one way of cutting budgets is to ask parents to bring in basic supplies.
Another example-at our state university the state supplied approximately 55 cents to the dollar of budget in the 1980's and early 1990's. It currently supplies just about 20 cents to the dollar.....so in a little less than 20 years the students have not only had to offset inflational costs, but also the decreased state funding of about 35 cents/dollar. Multiple that $0.35 times a typical $10K tuition/housing budget and wow! costs have really increased. And don't get me started about the textbook scam (and yes, I am a professor! I avoid textbooks and use online readings or original library sources whenever possible).
I wish I could say that my salary has greatly increased, and thus was greatly contributing to the costs, but I am a scientific research who has a PhD (8+ years of college) 20+ years of teaching, and I make less than my kids' elementary teacher with 10 years experience. If I were to into administration at the university, or go back to private sector research I could easily TRIPLE my salary (but I am stuck here with my husband in Corn Capital, USA!- he works for a private university with better salary and benefits!). I would be gallant and say that I do my job because I love my students.....well, actually, I do. But my pay SUCKS!
We will pay over $450 to just REGISTER our three youngest kids for PUBLIC school. Add another $300 in school supplies, plus PE uniforms, student activity cards, pictures and year books and we are easily over $1000 just to send them to school on the first day! Ugh!