Take everything out of the race car, then if something breaks add the last thing you took out back in. I imagine he'd get frustrated at a car still running on the victory lap.... "Darn, the wheels are still on we made the wheel hubs too strong."
The problem here is safety. Making a race car that disintegrates as it crosses the finish line is best for winning a race, but probably isn't terribly robust in an accident.
I don't think Musk is trying to make "barely safe enough" cars, but he is exploring a bunch of design limits. I think the CT specifically is an engineering sample or beta program for the model 2, designed to have low uptake and validate a bunch of _really_ big changes to "normal car" architecture. When some of those gambles turn out to be bad after 2 years, they'll have to fix thousands of dud trucks not millions of model 2s.