I feel as if any release rule set, if it could ever be seen as a good starting product to buy, would need to be written assuming the new player has no idea how to play an rpg. However I think that could double the size of the fluff in a book.
On the other hand releasing a product that assumes you already know alot about roleplaying games or a specific game runs its own risks. Such as being mis-interpreted or too hard to pick up and play without referring to other books.
I think that anyone could buy Arcana Evolved and learn to play it with no prior knowledge of 3e. That's a good thing of course. I just can't Imagine it being that impressive to buy a product and see the whole "What is a roleplaying game, and How to GM", sections, every time.
Maybe I'm just being lazy, I am thinking about releasing my Kurahast ruleset at some point. It could be a great set of rules for beginning and advanced players. I just can't imagine me trying to write, "how to role play and making adventures", sections, when odds are anyone who would see my ruleset already has access to tons of info on those subjects.