I think maybe it's worthwhile to make the distinction between 2 possible types of strap lug failure.
The first is the outer part of the lug giving way because the lug has worn thin by friction with the neckstrap ring over time. Pre the M4-2, the lugs were made of brass. Steel strap rings, being much harder than brass, would accelerate the wear. My M4 has some strap wear, but there's still plenty of thickness left. My M3's lug holes are oblong rather than circular, but since for me the M3 is only of occasional use, they'll probably last longer than affordable film and processing 😀 In any case, there's good visual warning of impending failure from thin lugs.
The second is the entire lug pulling free from the body. Through the early years of the M6, all the lugs are held on by a single stud which is crimped from inside the body casting. Assuming it was crimped properly in the first place, it should not pull out of its moorings without first giving warning by being wiggly and able to be rotated.
From mid-M6 until today, the lugs are held in place by 2 small screws attached from inside. This solves the rotation problem, and provides a failsafe against the lug detaching...unless of course both screws are allowed to come out.
As to the risk of using someone's homebrew wrist strap, you can't cheat the laws of physics, and hanging the camera by one lug puts twice as much force on it than a neckstrap, and places the force in a direction the lug wasn't designed for. Personally I'd prefer to just wrap the neckstrap around one hand.
