I highly doubt sales would increase by 10x, or even 2x.
This book isn't trying to sell itself by saying "hey, buy me and you'll be entertained for three hours, which is a better value than a movie ticket".
This book is trying to convince potential customers that it will help them graduate from junior engineer at local_company to senior engineer at FAANG. It's no coincidence that the author mentioned right here in his opening post that he landed a senior role at AWS. (I realize that's not a dream for many, and the whole FAANG thing is aggravating, but enough people think this way.)
If you (as a potential customer) aren't convinced, then you have no reason to buy this book even for $10.
On the other hand, if you are convinced, then the upside is so large that this book is worth buying even for $500.
Not many people will be on the edge pondering "I really think this book could help me triple my salary and status but that's worth $10 to me, not $40".
This book isn't trying to sell itself by saying "hey, buy me and you'll be entertained for three hours, which is a better value than a movie ticket".
This book is trying to convince potential customers that it will help them graduate from junior engineer at local_company to senior engineer at FAANG. It's no coincidence that the author mentioned right here in his opening post that he landed a senior role at AWS. (I realize that's not a dream for many, and the whole FAANG thing is aggravating, but enough people think this way.)
If you (as a potential customer) aren't convinced, then you have no reason to buy this book even for $10.
On the other hand, if you are convinced, then the upside is so large that this book is worth buying even for $500.
Not many people will be on the edge pondering "I really think this book could help me triple my salary and status but that's worth $10 to me, not $40".