The reason they have nice trucks, aside from their income, is that generally most of those folks have huge sleepers because they "need" them - to a degree. They stay out for 2-3 months, some longer, because they're doin' long distance stuff, usually more than 1,000 mile trips, with 4 to 6 cars or more onboard. They're kinda like furniture movers with the big sleepers as best I've gathered from talkin' to some of the fella's. They pull into LA with 2 Lamborghini's, a rolls, a bently and a Ferrarri... they may unload over a 2 or 3 day period in the LA area. Sometimes in the same location, sometimes not. Then they may sit through the week getting fresh cars back onboard... therefore, having a huge sleeper is worth it. The rigs aren't that much really, it's the sleepers and the trailers where the cost is really raised up. Usually it's a run of the mill Pete with a 120" sleeper on these specialty car carriers. The trailers are custom built trailers, with a low floor and padded walls. I've talked with drivers of Reliable (Auto Carriers with nice orange trucks/trailers, usually with polished out stainless/aluminum/chrome all over) and they tell you stories of using white gloves/special cotton gloves when working with the cars, so as not to put fingerprints on the paint. They wrap the cars in towels/cloth in many spots. Sometimes they'll put special tape in certain area's of the cars to protect it's finish. They have tie downs in the floors and they sometimes wrap the chains/straps in cloth to protect the cars as well. The back door is usually an elevator (like on a Nascar Trailer) for the cars. Sometimes they put the cars on dolly's so the cars don't get any extra miles (I'm serious), I've seen it done. The business is booming, I think it always has. Like they said in the above reply though, the drivers are hand-picked, their driving record is spotless, and they're people people with excellant communication skills - and business skills to boot. They're moving cars for celebrities, VIP's, and the very wealthy... they sometimes deal Direct with these people, so your not just a driver, your a Public Relations Person, Mr. Fix-it, and you have to take care of the paperwork and payments on the spot. They (The specialty car carriers) tell you stories of in some cases they even take cash payments or have to run credit cards on the phone with the customer right infront of you. Sometimes you don't even deal with dispatch, the customer calls your cell phone direct to ask your status and the status of their cars.
I was in NYC not long ago, and there was an auto show, and let me tell you, the average sleeper on the rigs out there around that convention center was about 120"+, and there was atleast 15 rigs like that, at the very least. All of them looks like you could eat off any part of the rig, they were that clean - spotless all around.
There's my 2 cents