fabie,
Tax cuts and a voucher system are definitely incompatible in any area where large numbers of children attend voucher eligible private schools. That is simple arithmetic.
Huge savings in could be achieved through school consolidations. This is true both for public schools and private schools. NY State has almost 700 school districts, NJ about 600 — but Maryland has only 24! Since every school district has to have a Superintendent, at a market rate of about $200k/year or more, that is tens of millions of dollars in Superintendent salaries alone that MD avoids each year, and the efficencies extend throughout the system.
And the same holds for yeshivot. Chasidic schools tend to be much larger than yeshivish or MO schools and the tuition costs are commensurately lower. But who has the authority to order a rabbi to close his school and combine it with another?