Example? There are plenty of examples where mistakes that Tesla's cameras make (being blinded by the sun, having trouble with emergency vehicles) are no problem for systems with more sensors.
I interpreted that statement by Karpathy as an accidental admission of Tesla's own limitations and not of the approach itself. (Note: I'm upvoting all your comments because they're very reasonable and supported.)
Specifically this is the relevant part: https://youtu.be/g6bOwQdCJrc?t=1370
They removed radar because it was making things worse.