Overflow incontinence happens when your bladder gets so full that the sphincters physically give way and you pee yourself. In other words the muscle would give before the bladder ruptures. I came across a thread about Tycho’s death on Reddit and virtually no one was calling bullshit on the story that he died of a burst bladder because he was embarrassed to go to the bathroom during a banquet.
Just because it’s generally possible for the bladder to rupture before the muscles give out, it’s certainly not impossible. A myriad of conditions or even just genetics can lead to a physically weaker bladder.
I think it’s a bit bold to say that absolutely 100%, no exceptions, that the muscles will always fail first. Even if that’s true 99.99% of the time, there’s just far to much variance in human bodies to rule it out, I would think.