There's a demand for them. SUV are quite popular for families who don't want to "drive minivans" but they still want a large vehicle to fit in everyone. Others buy it because of the perceived safety, larger vehicle so they feel more "protected".

Trucks are just what you drive in rural areas. And there are a lot of small towns and rural areas. Companies noticed that people are shelling out $40k for them, so they started selling them for $50k. $50k and they are being bought still? Ok, time to charge $60k, and so on.