^^Actaully, I think your description about the GRE supports my point QM, even though that was probably not your intent.
If you are saying a GRE taking xx years after undergrad (and after completion of a MA/MS) may not fairly represent undergrad grades, ok, but that is not the authors point. S/he claims that there are no alternatives, and in fact the GRE serves as just that even in your example. In fact, in this case, the GRE makes a low undergrad transcript almost moot. So in can serves as an alternative (along with MA grades).
The GRE does have higher level math than the SAT, but not very high as to exclude hume/lit majors. Also, the Verbal portion requires a much broader vocab that the SAT. But I do agree, that the MCAT (and DAT?) are probably the only pre-grad/professional tests that cover subject material. The LSAT certainly does not.
btw: the GRE changed its scoring last year to a 170 max.