Consider an airbag. It "only" increases the time for the deceleration of your upper body to O(0.1) seconds. The reason it's so effective is because O(0.1) is O(100) times larger the deceleration time without an airbag, making the acceleration O(100) times less.
The reason why an airbag is effective is prevents your head from traveling long distance so you don't break your neck. It's still painful and still can break your nose.
If they had retrorocket on the capsule, I suspect it failed.
The purpose of an air bag is to keep your head from smashing into the steering wheel or dashboard at 70MPH because the car stopped but your head kept going.
The air bag decelerates you to zero over a (relatively) much greater time, meaning much lower forces on your face, brain, etc.
Soyuz lands with a retrorocket and it looks exactly like this:
