Let's be honest here, this sort of situation comes from not properly tightening the bolt and never ever checking it, which is a basic check point in maintenance, or it is for me.
a properly installed crank will avoid this whole deteriorating situation and I've never had it happen to a bike, nor seen it happen.
it's like saying car wheels can fall off because the lug nuts can loosen.
How often do you check yout lug nuts? In any case, you’re comparing two very different designs as if they had a relatable situation. Actually I think there where car wheels that went onto tapered axles with a single large nut in the middle(like on old Brittish roadsters). We don’t use that design anymore...
People come up with better ideas and our stuff improves.