Weight is also an overwhelming factor in the OTHER person's survival in an accident. We do not make the general public safer by encouraging an arms race of heavier and heavier vehicles.
The problem is, that there are always going to be heavier vehicles than ours on the road. Even if we make everyone drive Volkswagen Ups or Minis, there are always going to be trucks on roads which will literally ride over such a small vehicle. Not saying that you would necessarily survive in an SUV, but chances are probably better. Also - people will always drive pickups and vans because they need them for work. Even if we eliminate all SUVs from pleasure/commuting use, there is still plenty of dangers that will remain.
The thrust of the argument would be that your are upping your chance of survival against a truck by lowering the survival of the people you might hit. I don't think the chance of getting crushed by a truck is very high compared to the risk of hitting a pedestrian or cyclist.