With AC, the arc will self-extinguish a half-cycle after the switch opens. With DC there is no cycle, and contacts can be completely vaporised in tens of milliseconds.
Commodity switching components are usually rated "30V DC, 250V AC" for this reason.
It is possible to design switches so that even DC arcs self-extinguish, but the result is expensive and not as reliable as one could wish.
If cars had been invented after 1980, they would probably use solid-state switches except for the very high current circuits such as the starter solenoid and headlights. (Transistors were around a lot earlier than that, but engineers are sensibly cautious about new technologies.)
Edit: To answer your question directly: no. Cost is prime.
You could also just switch the HV (400V+) bus directly down to 48/60V as all the high current devices motor/ac/power steering etc run off the HV bus and you would just be left with lights, entertainment and servos on the low voltage side. The 12V battery is probably a bit silly when you have a 50KWH main battery and 97% switching conversion efficiency regulators and I am guessing it may disappear in the next 10 years
I meant to the customer or owner, over the normal lifetime of the vehicle, not to corporate accountants that translate pennies into millions of dollars.
"More expensive" presumably is a small amount per car; the average new car in the US is over $40K.
Wouldn't a more important question be how does the failure mode change?