You can always find exceptions where somebody hiked out and was saved.
But your odds are much better if you stay with the car. All you're doing is playing the odds.
Yes, the only time I might try to hike out is if I could clearly hear the sound of vehicles on a highway (not an aircraft, which might pass once and never return). Even with a nearby highway in this northwest terrain, odds are high you would come to a steep section or a stream and have to turn back. These people were in a remote area and the father should definitely have stayed in the car.
Can't we just hold on to hope and best wishes for this man til he's found. There will be plenty of time to call him stupid and dumb and reckless, etc. after he's located.