I personally make the majority of my Amazon purchases through the Amazon/Kindle/Comixology apps on my phone, quite frankly because the process of doing it on my laptop requires several more steps (open laptop; open Amazon; re-authenticate with password manager; sign into Amazon; pull out 2FA token to complete sign in; find the thing; check out). For all the security trade-offs with Amazon's "1-Click" buy options, it really works. The loss of revenue is not going to be from things I research and plan to buy (e.g. if I order a new TV after hours of meticulous research), it's going to be the impulse buy's of $2 e-books and the like, where the added burden of logging in will force me to think about whether I really want this e-book enough anymore to finish jumping through all the hoops.
Maybe that's a plus in many people's eyes. But it's probably going to take a sizable hit on Amazon's bottom-line.