Not true. Look at the market for meat. There are lots of farmers, a small number (really three or four) processors (who appear to carve up the national market into non overlapping regions) and then a large number of retail customers.
To me that looks like an actual antitrust violation but the DoJ and FTC aren’t investigating bc they are obsessing about “big tech” uselessly and bringing bad cases they are going to lose!
If you want your regulators to actually do something about a lack of competition in the US economy (which they really should be doing!) there are a ton of markets worth investigating before they waste their time on this loser of a case.