One of the reasons SUVs and pickup trucks are popular here in America is that they're easy to get in and out of. About 1/3 of Americans are obese (far more overweight), and from my observations, many have weak legs and cores. SUVs are part of the same phenomenon that has popularized single-story suburban homes, bottom-freezer refrigerators, etc. I see it as less of a network effect and more of a feedback loop.