It is a lot easier for Amazon to add crypto payments than it is for you to build what they have.
It's also a lot less likely for Amazon to implement cryptocurrency payments.
That said, the chances of OP to be able to build an e-commerce website that's comparable to Amazon are pretty slim.
I don't know maybe it's possible to build something similar without having to deal with all the stock, I don't know something like drop-shipping from another well-known service, but then you won't be able to compete price-wise.