Supposedly, church schools have some advantage over public schools because they can use buildings that would otherwise be largely unused except on Sundays. Also, many parochial schools require students to buy their own books, don't have libraries, lunchrooms, bus systems, or special education programs (including for severely handicapped students) - so those can be significant savings.
It appears to me that there must be a bottom limit on how much expenses can be cut, however.
You wrote:
“Supposedly, church schools have some advantage over public schools because they can use buildings that would otherwise be largely unused except on Sundays.”
But in the process they still use them all week long whereas the public school may go almost unused all weekend. In other words, you’re saying the church based school will be open and running six or seven days a week. That’s not cheap!
“Also, many parochial schools require students to buy their own books,...”
But most don’t.
“... don’t have libraries,”
Most do.
“...lunchrooms,”
Most do. And do you mean a cafeteria that serves hot lunches? A lunchroom is just a room. A cafeteria that serves hot food is another story altogether. And many Catholics schools have those too.
“...bus systems,”
Catholic schools pay for buses.
“or special education programs (including for severely handicapped students)”
Catholic schools rarely have many special ed. programs because they are impossible to afford. That has not stopped bishops from requiring more and more services from Catholic schools in that regard without funding it in anyway.
“...so those can be significant savings.”
Nope. The simple fact is, if you got rid of the things you listed it would not be considered much of a school in the common American sense and parents would pull their kids out. Besides a lunchroom and library effectively cost next to nothing. Kids pay for the meals and the libraries have small budgets because kids rarely read books these days. Most school libraries are used as quiet places of study or as computer labs. That is true at both public and private schools - and even public libraries! Yesterday I dropped by the local public library and noticed that none of the teenagers were checking out books. Little kids were checking out huge stacks of books, but the teens had not a book near them. The teens were there to use the computers, update their facebook account, check email, whatever.
“It appears to me that there must be a bottom limit on how much expenses can be cut, however.”
Catholic schools across the country are at that limit. The local Catholic school district just cut a handful of teachers for financial reasons. If they can’t turn this around soon, they’ll close their doors for good.