One caveat, Dr. Phillips High School isn't your standard run of the mill sized school, it's huge and now has something around 3700 students. So, the cost involved will be much higher than most school projects especially considering the sports and arts program at the school. I remember that when I lived down there that the school was woefully overburdened with the number of students compared to what its build size was, which I believe was for 2300 or 2400 students.
My point is just that it's much grander than a standard school, you also need to have a school housed in close relation to where the current property is and there isn't much to go around for a campus of those needs, and it's naive to think that the county would do anything but charge an extremely high premium to sell the land. New schools are far from cheap today, so between the land acquisition costs and act build costs, I personally think it's a moot point.
While there might not be a profit motive, the pols of Orange County have a constituent cost and opposition to something like this idea would probably be sky high.