You have put your finger squarely on the exact problem: Seatbelts are an ENGINEERED solution for CERTAIN, SPECIFIC situations.
In all other situations outside the design parameters they may become a liability and a hazard to their users.
It is not something that can be mandated in a top-down fashion from central government regardless of the desired good intentions.
My favorite example: Ted Kennedy might not be with us today if he had worn a seatbelt on his drive in Chappaquidick.
Best regards,
I've been hit from behind, one time very seriously, slid on wet pavement, hit in the side and had people pull out in front of the car I was in and we went 40mph right into the side (not all on the same day of course!).
in none of those sitations except the last (1976) did a seatbelt not assist. Except in the last, I was not wearing the separate shoulder harness and hit the dash (1972 Mustang coupe).
sometimes there's nothing that can be done, and that's the case. Even wearing a seatbelt I was able to duck below the dash of my RX-7 when a deer stepped in front of me (I was going 65mph when I first saw him and got on the brakes immediately, but ducked when impact was unavoidable).