Parmandur
Book-Friend
I'm going to reprint what Erik Mona wrote when on Aug 16 the core rulebook was at 11 on Amazon's Best Fantasy Gaming list and the Bestiary was at 23 (see post #106 in this thread for the full text).
"The recent dip may not look great, but I think PF2e is still stabilizing after the initial boom caused by the release and finding its place in the top 100. My guess is it’ll secure a spot somewhere in the top 15 (or maybe even the top 10 or top 5?) and stay there for a few years, if everything goes well. To be honest, the Bestiary is doing a bit worse than I thought it would. Not sure why that is."
Now, the Core is at 32 and the Bestiary dropped off the top 100 altogether yesterday and is at 100 today. As has been stressed before, you can't take the exact number to mean too much, but this is missing their expectations. What is happening with the Bestiary? That can't be good if the second book I'd tell people to buy to play the game is dropping this fast.
My guess is that the Bestiary is the DM book, so it is probably going to consistently sell at 20-25% of the Core.