Generally they make more, but they spend more as well. It depends on your business savvy, and the loads you take. Shorter runs equals less fuel cost. More money. O/O's that run for bigger carries will get fuel surcharge which helps but you'll have to run there loads.
its 6 of one, half dozen of the other. owners make more money but have to pay for everything and take care of everything. company guys just drive basically. so it all depends on what and how much your willing to do.