The H2 is exceedingly good at its purpose -- to be formidable-looking, large and heavy and conspicuous. It's a car for showing off, and it excels at that. But most people buy SUVs not really for showing off, but because they feel small = vulnerable. They equate size with durability, ruggedness, safety, etc.

By the way, it's not entirely fair to point to what toys kids play with. Kids love playing with planes and spaceships and those are or can be monstrously inefficient, but who cares? They're not worried about what the fuel consumption would be on the toys' real-world counterparts.