One of the ironies of modern bike design. BITD a rear wheel falling off would have been unheard of because he QR had to be bulletproof tight to keep the wheel from slipping.

Also, QRs and hubs had serrations to bite the frame and maximize hold so they were secure. Lastly, the QR nut had a friction system of some kind that made it hare to adjust, and kept it from moving when the wheel was off the bike.

However over time things improved.

Lawyer lips were added to the fork, which solved one possible problem, but required that the QR be readjusted each time the wheel was installed. For the life of me, I can't understand why designers assumed that someone who couldn't use a QR in the first place would magically know how to adjust it properly.

In order to save weight, and not leave objectionable tooth marks in dropouts, the steel serrated faces were replaced with smooth aluminum ones. This was made possible with the advent of vertical dropouts and layers lips on forks, both of which reduced the required holding power to work properly.

So, the combination of vertical dropouts, soft face QRs, and the need to adjust the nuts, created the real possibility that a rear wheel could be ridden with a loose QR and fall off when the bike was transported.

I understand how it could have happened, and feel sorry for the OP, but other than blaming the world and progress, he has to accept that this was likely user error and take it on the chin.