Freight always gets cheaper as more people get their hands into it. It doesn't mean it's "cheap" at all. A backhaul is any load from a source other than your own that puts your trucks back where you want them.
Someone running for Express-1 might get info to pick up a load for Bolt Express in a certain town. Some might argue that that could constitute a backhaul, so to speak. E-1 isn't making as much off it as with their own customer, because Bolt is keeping a piece of the pie. Suddenly, competitors have found mutual benefit in helping each other. Bolt doesn't have to say no to the customer, and E-1 gets their truck loaded that much quicker, moving them towards an area where they themselves have a stronger customer base. It's called cooperation. It's not necessarily called cheap.
It's amazing that I've been contacted by carriers within the Alliance that just don't get the concept, so their trucks suffer. We need help on moving a customer's load in Florida. Let's say we book it for an all in rate that comes to about $2.70 a mile. Various people including your carrier might give us quotes all around $2.00 per mile mark. (They then pay your str. truck 1.60-1.65 a mile.) Suddenly one guy emails me, quoting me $2.70 per mile. He's offended when I tell him that someone wants to do it for 1.90. His reply is, "This isn't a back haul load, it's a hotshot." I reply, "I'm just telling you what my partners are quoting me." Then I say, "Of course it's a hotshot load. It's just that it's not YOUR hotshot load."
Because that gentleman was unwilling to book anything for his truck that he couldn't make 45% on, his trucks only had one way freight out of their hot zone, then must DH long distances. It's really sad.