There are several disposal models. Cigarettes and alcohol, probably easy to unload. Someone tries to sell you a bottle of Whiskey or a pack of cigarettes at half price, well, OK, so what if you lose $20.
For specialty items - car parts, industrial supplies - presumably the theives have a distribution channel lined up ahead of time. Still, it would be one-off. You might unload a truckload of cheese or motor oil, but you can’t do that every month, you’ll plug the distribution channel.
For big items like TVs - well, where are you going to put 500 large flat-screen TVs while you try to find buyers? Besides, how would you sell a hot TV? Approching guys in parking lots works for one item shoplifted, maybe. Approaching enough people to sell 500, you are guaranteed to be turned in before the load is gone. Who’s going to buy a $1000 TV, even for $200, unless they can try it out first? Better, again, to have a distribution channel lined up. The danger, though, is that even if it’s sold through “Joe’s Bargain Shop” sooner or later someone will need service (or it will be stolen, he gives the cops the serial number) and Joe will have a lot of questions to answer.
Actually, I do know them, and when I was in the business it was some boys from New Jersey whose last names all end in vowels.
Here’s an article about a stolen truckload of 3 million nickels…