My wife and her late husband did just that when their children were of school age. They ran the school for over 20 years. When her husband died, and her youngest child entered college, she sold the school.
The parents took a lot of responsibility for the funding and operation of the school. It's not easy, but it can be done.
Here’s an example of parents pulling resources in my area - they developed a complete accredited program. It is pretty much between private school and homeschool but only around 1/5th the cost. The parents and teachers are partners; but it is still parent-led.
http://www.thekingsacademy.org/
Here is a local sports program too:
http://www.crownknights.org/
And this is one program, there are 4 more like it just in my county!