They probablly owned it for a while and it increased in value though? Appreciation of value for classics is different.You're the idiot, my dad has an SL/R 5000 which is insured for $35,000 more than he bought it for.
Think about XB, XA, XY, XW Falcons (particularly the GT's), LC, LJ, LH, LX Toranas... i know plenty of people who have made money on their projects.
If you do the work yourself in a restoration, then sure you might get the dollar value back, or more, but that's because you've put in your labour value, and your time labour is no different to hard currency.
If it were possible to buy a wrecked classic, pay someone else to do it up, and sell it for a ten grand profit, everyone would do it.