Being that we are falling behind on education compared to most other modern industrialized nations, perhaps instead of doing away with the 12 grade to save a buck, why don't we keep seniors busy and challenged academically through the 12th grade.
I would suspect that most people behind doing away with the 12th grade are those that disagree with the entire notion of a public education system. Of course in that case, its not out of pragmatism, but rather some irrational opposition to all things government. I really think it should just be diagnosed as a phobia and treated for lunacy that it is. Nations that don't have a public education system are not exactly a paradise. In fact, they are pretty much all 3rd world **** holes.
For the extreme libertarians, the idea is not to just do away with the 12th Grade, its to do away with the entire public school system. You see it will start with this, and then they will just say "well if you want to go through the 12th grade they can just charge you a fee for it" and then on down the tubes with the whole thing.