Not that simple. The vast majority of the PayPal alternatives out there right now are US-only, so any business that's either outside the US or has any customers who are is pretty much stuck with PayPal - or with direct credit card processors that cost a lot more and don't allow customers to pay by any means other than credit card.
I'd love it if there was an alternative that was available internationally, not credit-card-dependent, and was as easy for customers to use as PayPal, but I haven't found one yet.
Amazon doesn't take PayPal, at least not as of last I used it. They're big enough to dictate their own payment terms and ignore users who don't have credit cards. PayPal's main user base tends to be smaller businesses, who are likely to care more about accommodating everyone since each sale counts for more with them than it does with a giant like Amazon.
And unfortunately, they've pretty much cornered the market there, because there aren't really any other payment processors - that I've been able to find, anyway - that are available internationally and don't require credit cards.