I think that the general mistake (and is probably a debate on its own) there is to compare Japan and like where i live in Ireland... to the states, ye have access too way more of these bikes over in USA
I don't really have a good sense for how the exchange rate, which is tied up with a lot of economic complexity, reflects the cost of vehicles purchase and ownership. But $43k USD is a lot of money for any vehicle here in the US, especially a motorcycle which is generally considered more of a toy than daily transportation. Looking at the top models for new bikes, the most expensive HD I can find is the 2021 CVO Limited at $44k. The over the top 2021 Kawasaki H2R is $55.5k. The Ducati Panigale ranges from 21k to 40k, with 243hp for the top model. But you can get a whole lot of motorcycle for much less than that. The ZR10R ABS is $17.4k
Going off the exchange rate, the idea that a 40 year old mass produced bike would be roughly the same price as some of the most expensive and ridiculous bikes available in the US is surprising. The exchange rate either fails to capture what vehicles cost in Japan, or shows that the Z1 derived models are
really really desirable. As desirable as the very best modern hardware.
Oh and p.s DOHC my dream is to build that exact bike that you used as an example.
The Sanctuary bikes are all stunning works of art. I have often dreamed of trying to import one. I have also wondered if it would be possible to send a frame to Japan for them to rework.
Do you think they would brace up my frame, and send me back a big pile of really trick parts, like some kind of Sanctuary bike kit-in-a-box? I can dream, right?