I notice a lot of diesels sitting in driveways for years. I know of at least six right now. The people usually get tired of trying to service them and opt for a newer gas auto. I got my 76 300d w115 for $100 and now drive it daily. It needed about $600 of parts and DIY work. I am thinking of doing the same with an 82 turbo. The salvage yards will give $100 and tow it away.
My 76 had been sitting for four years. I put in new glow plugs, new battery, adjusted valves and it fired right up. At that point I knew I had a "runner" and did the rest of the work to it. If that hadn't worked I could have parted it out on E-bay and got my $100 back. To most people diesels are a pain in the butt, especially the older ones. They usually go to the dealer for service and the cost becomes prohibitive to them so they just buy a new car. I have heard this story many times. Usually with 120-160k on the odometer.