I used to routinely get gamebooks from Amazon on or before street release.
Then something changed, and Amazon started waiting for two weeks after street date for a lot of game books. I suspect that brick-and-mortar stores complained loudly to the publishers, but I dunno.
Anyway, it's usually not a big deal for me to wait, especially given the savings Amazon provides. In this case, though, I would rather pay a higher price and give my money direct to Paizo. (And that's saying something. I'm not cheap, but I am frugal.)