Why didn’t his wife ask to have it re bagged in two separate bags?
Because that would require a) critical thinking; b) responsibility for one's actions.
These have been bred out of the species over the last 50 years.
I’ve had that happen, where the checker failed to double bag some heavy items. I wasn’t killed or injured, obviously, but cleaning up the glass and contents of two large jars of sauerkraut was no fun.
I ask for items to be double bagged and sometimes the handles still break. This was at my grocery store. They are not made like they use to be.
The glaring omission in the story is the lady's age. That might have triggered the need for a reasonable judgment that perhaps she needed help, or special bagging.
Most elderly are reluctant to complain (yes, there are exceptions) and I wonder how many other relevant facts may have been left out of the story.