This isn't really a good-faith argument (for Amazon or SA) because of the reliance of opinions inherent in the word "need".
It could be argued Amazon only "needs" one domain: Amazon.com (or com.amazon, heh). It could also be argued Amazon "needs" 1,000 domains (aws.amazon, books.amazon, electronics.amazon, prime.amazon, videos.amazon, etc). Who's to say who's "right" in these opinions?
Nobody really seems to care about what the most "right" domain is, anyway. Ignoring the mess that is .com/.org/.net, it's a daily occurrence to see .ai domains outside of Anguilla, .ly domains outside of Libya, etc.