I agree with everyone that one should not live like that.
The problem with Terri Schiavo, is that her husband would not pay for some expensive procedures earlier, before the courts were involved, that would have most likely been able to determine her possibility of recovery or attempt at some sort of life. He wanted the money for himself to spend.
The doctors probably could have been able to see that her brain had shrunk to half the size of a normal brain. And determine that she was no longer able to see, due to the visual centers of the brain being dead. But her husband would not pay for tests that would have determined the findings in the autopsy.
Overall it was sad that she ultimately had to be starved to death....