"EVERY A body has this problem"

I bought a used Swinger 340 in fall of 70. By 73 or 74, I had to have this repair done.I think I got it done on warranty,lol. I think if you don't drive them then they don't break,lol. I wore everything out on that car, some stuff, twice!Except tires. Man that car ate tires.And synchros.
After that I learned to adjust the door hinges more often and to not lean on the open doors.
I've had many As that were cracked there , from 40% say all the way to 100%. Actually the more I think about it I can't remember but three of them not being cracked, out of say at least 10.