I thought the same when I took a peak, but then I thought about it. I don't like everything on it, but 67k original miles and zero rust. Every nut and bolt replace... All things considered, I doubt you could go out and build the same for less than 40k.
You and I think like people who would do this from the ground up, the way we want, but the BJ folks see a sweet FJ40 and don't even notice the fender flares, wrong color bezel, 90* shackles.... and so on.
The $30K price it sold for is actually a pretty good price for someone that really wants a nice 40 and does not want to do the work.
We all know the costs of building a cruiser, nothing about it is cheap. Think about how far $30K will go toward a full frame off. I have a 40 that I plan on bringing back to almost stock. I probably will not do anything other than get it drivable for another 4-5 years.
I think the days of finding good deals on 40s, even 60s are coming to an end. Old rusted down barn heaps are bringing thousands to people that know what they are selling.