Bligh, nice theory, but you failed on one key point.
Cat doesn't own the dealerships, they don't force the dealers to run their businesses in the manner desrcibed by the OP, they don't set labor rates, and they can't control what parts are sold to the consumer for. Clearly there are markets where this model works, and markets where it won't. Go to a waterman's town like Crisfield, MD and you will find a dealer like T&S Marine. One of the larger Cat and Cummins dealer /rebuilders on the East coast. There business is built on volume with low overhead. They ship to much of the East coast and out of the country because of their prices. No fancy show room, just a squared away shop with 8 or 10 employees, well stock parts room, and a seperate building with maybe 100 to 200 motors waiting to be rebuilt when they're sold. Genuine Cat and Cummins parts sold at substantial discount, and honest labor rates that are probably 60% of the FL boutique dealers. While most of their business is rebuilding engines, you'll find them working on a waterman's work boat, a million dollar sport fish in OceanCity, and the occasional yacht. Same quality of service as the boutique dealers, but for a whole lot less money.
Ted