In the United States, a large share of passenger vehicle sales are for what are essentially station wagons. I'm referring to SUVs (sport-utility vehicles) and "Cross-overs," (passenger car platform versions of SUVs) whose market share in the USA for the first six months of 2013 was 37 percent. Their market share where light-duty trucks are added to the mix was 23 percent.
When I used the phrase "essentially station wagons" (or "brakes" as they are called in Britain and some other parts of Europe) my point is that the interior layout of the cabin for SUVs is the same as it was for traditional station wagons. That layout is comprised of: (1) a front seat area for the driver and passenger; (2) a seat behind that for passengers, the seat back designed to fold forward to increase cargo space; and (3) a roof-high area at the rear for cargo or, in some cases, a third row of seats.
What made station wagons and SUVs practical was the 1949 Plymouth's introduction of an all-steel body for the station wagon type car.
Original 1920s and 1930s station wagons, in the American sense, were sedans or perhaps light trucks that were given a long, box-like passenger/cargo area that extended to the rear bumper. These vehicles were used to meet people and their luggage arriving at a (usually) rural train station for further transport to a hotel, resort or country residence -- hence the name "station wagon."
This special bodywork extended from the cowl/windshield of the car to the rear bumper and was constructed mostly of wood. Since most cars of the 1920s and early 30s had bodies framed in wood (with metal cladding), this was simply an inexpensive means for yielding handy station wagons, a very low-production sort of car in those days. By the late 1930s, car construction became all-metal, yet station wagons continued to have wood for the passenger/cargo area (though roofs might be metal). These station wagons could not be integrated into a normal production line, thanks to the use of wood. So cars with partly completed bodies would be pulled off the line and sent to a special shop or an outside contract builder for construction and installation of the station wagon bits.
By the 1940s, use of wood construction for station wagons had become a matter of tradition rather than practicality. For example, the special assembly mentioned above usually made wagons the most expensive body type for a brand. Then there was the matter of maintenance of the wooden bodies. They came from the factory varnished for weather protection, and the varnish had to be maintained, an expensive, time-consuming task. (Many owners gave up maintenance after their wagon was a few years old, so older models often got pretty ratty looking.)
The obvious way to reduce purchase and maintenance costs -- in turn, encouraging increased sales -- was to simply eliminate the use of wood. But it took until the 1949 model year for that to happen in the form of the Plymouth Suburban.