To lose the clash, I would understand, but to break the sword? Your explanation makes no sense whatsoever.
Madara's PS can slice up mountains from another country. That specific sword was created by the Juubi's malleable chakra, that same chakra whom protected Juubito from 4 Bijuu Bombs going off in a barrier. What I'm saying should indicate how defensive that stuff must be, besides, it's not a crazy assumption if you say that the Sword of Nunoboko is more powerful than the sword of Madara's PS, since it was an item owned by Rikudo himself.
Let's be realistic, it does not make any sense whatsoever, and Kishimoto isn't perfect either. This is something you, and more people, should understand.