Earlier quoted context omitted.
Amazon is in a low margin commodity business with massive amounts of competition, but they're still massive and becoming even bigger because they do what everyone else can do just that little bit better that there's no real reason to switch away.
Amazon actually didn't have much competition at a key point in it's growth, i.e. just after the dot com crash. Amazon survived, many did not and Amazon then had a few years to cement their dominance in the online shopping space. Amazon is also very different from Uber in that it a) went public earlier and b) didn't need huge outside cash injections like Uber and c) Wasn't making a huge gross loss on sales like people…
Except for every single brick & mortar store -- which has always been Amazon's biggest "competitor".