Our society will "work through" all the vehicles on the road today. They will not be converted to electric (OK, maybe a hobbyist will try one somewhere!).
Values adjust in the used car market to reflect hard facts like mileage, age, fuel mileage, and what people want to drive. When that value gets too small to continue with repairs, the vehicle will be salvaged or junked.
Vehicles get "repurposed" too. Your question hints that you may think the Cadillac Escalade and other SUVs will stop being driven. That won't happen, but why they are used, how much they are driven, and what they transport will evolve as other choices come available. These changes will reflect in the value.
