We've talked about this before: That the super-hard stainless steel will, in fact, crumple. The forces in a collision are many, many times more than a sledgehammer can put out. Now, everyone remembers the steel for the Cybertruck uses the same steel as in the Starship from SpaceX, right...
Here is a great deep dive by Nikola Garage into the history of stainless steel construction in the auto industry, the nature of stainless steel, rust, and why the Cybertruck body and frame "should last forever.”