Because we have SUVs, they are "image friendly."

Actually the real reason is worse than that - the image has been created and molded by the manufacturers to sell SUVs. The reason we have so many SUVs is because of the legal loophole that prevents many of the modern emissions and safety laws that apply to cars from applying to them. SUVs are classed as a light truck, ie like a pickup truck. US manufacturers found it more profitable to create and manufacture SUVs than to make wagons that complied with new laws. That is why a US made wagon is hard to find now.

European manufacturers don't have those loopholes in their core markets so they kept refining wagons, hence the reason that Audi, VW, Saab, Porsche, Mercedes Benz, and Volvo all have various wagons on offer.