I managed to snap an xt crank that was over 10 yrs old by rubbing my heels on it over this period, just fell off while I was riding along a canal towpath. I’d been waiting for it to go, I’d rubbed a hole in it a few months before it gave way. Replaced it with deore because that’s what I had lying around in my shed.
Only other crank snapper I’ve known in 30 years riding is my son who in his teens snapped a solid crank on a road bike when he was in a chain gang. I had to drive 40 miles to collect him. This was 20 yrs ago.
Still, most of the things we worry about won’t happen so maybe the OP isn’t so far wide of the mark