Government passes mandatory seat belt law. People still don't wear seat belts. Government requires passive restraint system on cars. Some car manufacturer go for air bags, some for automatic seat belts. People hate automatic seat belt more than the manual ones.
Car makers go with the air bags.
People still don't wear seat belts. Air bags start killing people. Government adds rules, regulations, and punishments for air bag use. Let's follow that logic - If air bags are as good as automatic seatbelts, and manual belts are as good as automatic ones, then air bags must be just as good as manual seatbelts. But people don't wear them.