The entire industry, small and large fleets, use owner operators as perverse cost savings. In some cases, you lease the truck from the large fleet, they charge you for gas and maintenance, insurance, etc; deducted straight from your check. You integrate with their comms / cpu systems, their tracking systems, etc. all for a price. You go where they tell you and when.
It's an industry that's almost impossible to run profitably as an owner operator, because those folks are skinned. But, people are in love with the idea of owning their own business - it's kinda like an MLM that way.
Now, I founded a trucking company that had as many as 15 trucks that ran over the road, both owner operators and company owned vehicles. At my size, there were very few economies of scale and we ran at a break even, at best - closing after a few years. We paid teams .40 cents a mile, all miles, backing out the per diem and paying SS / payroll taxes on the balance - an ridiculously high workmen's comp (first year was 24%, went down to 16.5% later).
I could go into more detail, but you get the point.