The "extended warrantee" is definitely a for profit business, but much different than selling the truck or camper. There is many times the profit in selling the warrantee than in selling the truck. Many dealerships are happy to give you the truck at their true cost if you will just buy the warrantee. The proof of this is in how diligently and forcefully the sales people pursue the warrantee sale.
Also, there are extended warrantees offered by the manufacturer and those offered by a third party. While both are overpriced, the 3rd party ones make it their business not to pay claims - after all, claims come right out of their bottom line. It is a little different for the manufacturer, as they have a brand and a customer to protect. I've bought only two 3rd party warrantees on products, both proved to be worthless when needed.
Finally, if you pay the retail price for these you are paying 2x or 3x too much. For automobiles, the exact same manufacturers warrantee is often available from a different dealership for far less. I rarely buy these, but the repair costs on a new diesel truck where even small problems can result in a "cab off" repair are a consideration, so I bought the longest one offered. After negotiating with the dealer who sold me the truck, I got it down to around $5K. But I walked and purchased the same Ford warrantee from a dealer 3000 miles away for $1800. I'm sure they made money on it.