Repairs and parts availability is one of the biggest risks. Could easily see situations where a small fender bender causes a total loss.
So yes the rapid progress means that the older cars depreciate quickly. This is only get worse with the next refresh rumored to be fairly soon.
The biggest hit to value came with the Tesla price lowering.
Id expect a 20% loss but not 50%. Porsche and Lexus don't lose 50% the first year.