Bone yards have no real incentive to keep anything past the 15-yr mark. Plus, the auto dealers, the chain stores, etc, tend to get rid of stock at that point. The vehicle has also declined to it's lowest resale point.
Worst of all, the electrics make it prohibitive to repair. In no way would I bother with a vehicle that old anymore. And, when health allowed, I'd only mess with -- preferably -- pre-1971 cars for the ease of keeping them running or tracing electrical problems.
Unless one has a very popular vehicle, one with utility still in it (say, a 1988 Chev pickup), the inventory collects dust, and the body shop business has disappeared.
The local mini-mill south of Dallas eats dozens, if not hundreds of flattened cars weekly. I used to have a little fun getting the attention of the flatbed drivers carry a half-dozen squishies when in my 30-year old Chrysler. We'd both have a laugh.
And you can't travel a major north-south highway nearing the border without seeing caravans of Mexicans driving & towing old cars to the Rio Grande. Day or night