This can be true and still be not so great at the same time. What any company like Amazon tries to do is capture revenue, typically by taking it away from someone else rather than create something new.

In the short term that can mean a boon for small business as large competitors to Amazon are undermined. In fact, Amazon uses small sellers to do the undermining. Once everyone in a market segment essentially works for Amazon then they are free to tighten down the screws and extract more profits.