Much of whart I've been posting is not about 5th ed vs Pathfinder. It's about using Amazon numbers as a proxy for understanding how well it's going overall. This is commonly done when you don't have direct information. I don't trust the numbers as a direct measure of sales. Instead what I can reasonably assume is that if there is a noticeable rise or drop in sales on Amazon, there may be something similar overall. It's not a direct 1 to 1 correlation. Amazon also is probably where a lot of newer and probably more casual gamers are buying their books, so it's also a proxy for how many new players are coming in.To be fair (and as mentioned before in the thread by multiple people) Amazon is a not the greatest gauge to estimate sales / interest in Pathfinder.
One of the reasons 5e is doing so well on amazon, is because it is the main outlet to purchase it online.
Want to buy a 5e book directly from WOTC? You can't. You can buy a PF2book from Paizo.com however, in fact you can get a subscription and have them ship you one every time they publish one.
What a digital, pdf copy of a 5e book (Not a online database, like Curse's DND Beyond)? You can't You can get all of the Pf1/Pf2 books in pdf from Paizo.com
I guess what I am saying is that if you are a Pathfinder/Paizo fan, there is a large chunk of the market that is buying them online direct instead of amazon, where for 5e , it is the main outlet of sales.
So of course this is not the end all and be all of sales and may only capture a percentage, but we can still use it to try to suss out the health of the game in these early months.