There has been a procession of stigmatized vehicles reminiscent of the euphemism treadmill. That linguistic principle shows that one term replaces another as society's perception of it changes. Thus "idiot" becomes "mentally retarded" which becomes "developmentally disabled". Another example is how "shell shock" becomes "battle fatigue" which becomes "post-traumatic stress disorder".
Similarly, a station wagon was the classic way to haul the maximum amount of kids and stuff from the 1950s through the 1970s. By the 1980s these were perceived as "square" by the young adult car buyers that had grown up in them. The minivan was conceived as an alternative shape that still provided five doors and a maximum amount of space mounted onto a new front-wheel-drive unibody. It served the same function but looked sufficiently different.
By the time the 1990's and 2000's rolled around, the minivan had acquired the same "mom-mobile, grocery-getter" stigma that station wagons had had previously. Enter the "sport-utility vehicle". Changing over to a truck chassis to combat the reputation for mushy handling and to bring four-wheel drive to moms across the snow belt, SUVs became a hot seller that still delivered five doors and a maximum of interior space.
In the mid-2000s amid high gas prices and reports of roll-over problems, smaller versions of SUVs, dubbed "crossovers" came out to replace what was now seen as big, hulking relics. Still, five doors and a squared-off rear passenger compartment, although with slightly less interior space and smaller engines as a concession to fuel economy.
People still have the same functional space requirements, but they don't want to drive something that looks like their parent's or grandparent's car. So the treadmill keeps running...