When Prichard says that real life is clearly better than a Brain In Vat ('BIV') life, my immediate reaction was no, perhaps in fact it doesn't matter, at least perhaps not for the reason given. It could only matter to someone who is outside of the scenario. If my life is actually a BIV or 'Matrix' type setup then I'm not sure I really mind! The simulation is so good that I have no complaints.
It is not authenticity that turns me off the BIV scenario, it is the possibility of deception or manipulation and the quality of the copy or simulation. If governments decided that it was preferable to turn all citizens into BIVs, lack of authenticity is fairly low down the list of reasons why I would be uncomfortable.
If BIV was the only option - the only game in town so to speak, then it would be silly to "mind" that life wasn't "real", again we would not reject it for lack of authenticity.
Going back to Prichard's example of the two books (one a copy and one the original) - in many ways it is silly to prefer the original book, just as it is a bit silly to pay tens of millions for a work of art when you can purchase an indistinguishable copy for much less. Again, I think it is the deception or manipulation involved in copies which is the issue. Is it really rational to prefer the authentic book if it is completely indistinguishable from the original, and always will be?