Commercial Car Journal (published by Chilton -- the same people who produced automotive repair manuals) was one of the two dominant trucking industry journals during the time I was first starting out (the other was the weekly
Transport Topics which featured terminal properties for sale or lease, and stock prices for small truckers -- sometimes traded OTC.
But at any rate, every summer
CCJ would produce an annual "Top 100" of truckers ranked by revenue. But this hierarchy could be distorted by how companies were classified -- "truckload", (or more formally called "irregular-route, specific-commodity" carriers) were excluded in favor of the more tightly-regulated "regular-route general-commodity" carriers like Consolidated Freightways, Interstate System, Associated Transport and the rest. UPS was still in comparative infancy -- and it was split into two companies which still ranked in the top ten of
CCJ's listing, and FedEx, just getting started, was an afterthought.
That was nearly fifty years ago, and a lot has changed;
CCJ has expanded its listing to a "Top 250", but the ranks are dominated by UPS and FedEx with revenues of several times any of the "also-rans" such as Schneider, Swift/Knight, and Werner, which are truckload-oriented.
https://www.overdriveonline.com/wp-cont ... -15-25.pdf
As for the "contenders" of the earlier day, many of them quickly fell by the wayside as deregulation took effect; even small carriers, which sometimes dominated small markets, quickly went bankrupt. Consolidated Freightways saved itself by splitting into several regional companies. Yellow and Roadway, two acknowledged leaders, merged, (but are still struggling), and Arkansas Best (ABF) supplemented its revenues by getting into the household goods (consumer moving) market.
The "Era of Regulation", roughly 1934-1977, was characterized by a system in which the general-commodity carriers were treated as if they were railroads, with routes specifically defined -- thus could also lead to a scenario where smaller carriers could still dominate over a limited area, and some of these could be driven out of business quickly (and their employees rendered superfluous) by deregulation. Still other companies (Estes, R&L, Saia) took up much of the slack and prospered,
but (and because) they are no longer obligated to serve all comers equally -- small or mixed shipments are sometimes turned over to UPS or FedEx for local delivery.
"Oh, the more it changes, the more it stays the same,
And the hand just rearranges, the players in the game."
(Al Stewart,
The Eyes of Nostradamus)