I might agree with you if this sentence used a generic term instead of "Amazon". However it specifically refers to Amazon.
I think people forget that Amazon did not operate as a middleman when they first appeared in the early 1990's.
Amazon was originally a bookseller, not a middleman for other sellers.
Not only does the sentence above from GP assume the existence of Amazon, it assumes that Amazon must act as a middleman for other sellers.
I might agree with you if this sentence used a generic term instead of "Amazon". However it specifically refers to Amazon.
I think people forget that Amazon did not operate as a middleman when they first appeared in the early 1990's.
Amazon was originally a bookseller, not a middleman for other sellers.
Not only does the sentence above from GP assume the existence of Amazon, it assumes that Amazon must act as a middleman for other sellers.