"Lawsuit" insturments are hit with a double whammy of unreasonable inflation.
One, they're "vintage." In a world where the poopiest no name '70s Japanese junk is on ebay for $400 to start, you're up against an unreasonable expectation that "old" means "vintage" and vintage means 200% markup.
Two, they're "rare" because of a lawsuit that was, as far as I can tell, not nearly as big a deal as people think. Suddenly, even models not actually considered a "lawsuit" insturment is lumped in because it's shaped like an EB or a Rick or whatever, even though the actual lawsuit was over the headstock and the one you're looking at isn't actually a lawsuit model.
Just like when you could walk into a thrift shop and find Jazzmasters and tube amps for cheap because no one wanted them anymore, well, they got discovered and now they're gone and people want unreasonable cash for them. So too are Japanese junkers (and the rare birds that aren't junkers) are having the same issue. I can't imagine paying more for a "lawsuit bass" from the '70s when there's so many quality insturments going for less, but I guess people are treating it like investments or something.