They didn't need to introduce them, they saw the opportunity to do so. Besides, there's always been the possibility to buy a utilitarian pick up truck but they're work vehicles.
It's just supply and demand. Someone offers SUVs and Trucks, people buy them all, other companies offer more of the same. So of course, everyone who wanted to buy one made the concious decision to do so. The consumers are, in fact, responsible for their actions.
Guess why there are so few station wagons in the US now, as opposed to the 1980s. People wanted bigger cars and the market phased out the more sensible, but less desired option.