They tend to go $16k-$22k, race-prepped
with a pedigree.
A roller is might be worth up to $2k, depending on condition.
I looked into them for vintage racing at one point.
You're not missing anything - just another case of someone who thinks they're sitting on a goldmine. Meanwhile, what could be a nice car for someone willing to put in the time, shamefully rots.
If it's complete, the engine isn't seized, and there's no major bends or rust through in the chassis, I'd give them a standing offer of $2k.