Having scripts available doesn't stop people watching movies and having scores available doesn't stop people going to concerts.

Right, but I think people are so used to the relationship of podfic being a secondary format of written stories that it would have to be marked as different in some way (like having it in a .txt or .rtf file or something) to shake up this kind of thinking. Movies and concerts didn't have the same history of being seen as secondary to a written artform (that I know of) so it may be that podfic creators in a challenge like this would have to be a little more thoughtful about how we present the text and non-text components than a creator of one of those would have to be.

I agree with your overall point that both should be made available from the beginning, though.