I have been wondering why the U.S. seems to have moved so far from the trust-busting days of Teddy Roosevelt, and why it now seems so permissive towards monopolistic practices. This helps explain it https://en.m.wikipedia.org/wiki/The_Antitrust_Paradox

It is absolutely not. On every level there are healthy competitors: Shipping (Ocean freight Cos, Trains, Trucking Cos, UPS, FedEx), Online Sales (AliBaba), General Goods (Wal-Mart)

These are all very healthy competitors, it's just that they are all operating on a massive scale.