Anyway, besides that, there's not really a demand for paying in BTC. Most people are Hodlers or speculators, only a minority are trying to live the crypto life. From a business point of view, especially for a company as big as Amazon (since we're talking about it), why bother implementing something, with the work involved if afterwards nobody uses it, and it doesn't help increase sales.
You are absolutely right here, because in the event that Amazon receives dozens of inquiries every day about the possibility of paying with Bitcoin, perhaps this option would be available by now. It’s hard to say what percentage of people use BTC as a currency on a regular basis at all, and I think there are less than 20% of those who do, while at least 50% have never experienced paying with BTC for a good or service.
Regardless, I don't think that integrating crypto payments into their system would be complicated or too expensive, but that problems could arise between users -> customer support, because there would certainly be a lot of confused users with the questions
"I sent BTC but the transaction is not confirmed more than 24 hours " or
"I sent BTC, but the payment is not visible at all".