There are quite a few in the canyons in SoCal.
Not sure what the criteria would be for extracting them, but likely it would be suspicious deaths or celebrity status ?
I know of an old Mini that went over a cliff in Topanga Canyon in the '90s; it was extracted & sent to a salvage yard, but it wasn't more than a couple hundred feet down.
No celebrities or death in that one; just stolen. So likely insurance wanted it to determine method of entry or something.