Yeah, this is pretty standard. Between the low production numbers and the fact that assembly is probably occurring in a country with stronger labor laws than wherever mass-producted hardware is made (mostly China), it’s going to cost more than something you can pick up on Amazon or AliExpress.
There have been a few cases where open-source hardware like this has enough demand to get picked up by a Chinese manufacturer who makes a cheaper version through some combo of unethical labor practices, production scale, employing cheaper or cloned parts and/or dropping features, so it’s not out of the question that a cheaper version comes along, as long as you don’t mind the compromises to get it.
For years I thought Mickey Rooney (1920-2014) and Mickey Rourke (1952-present) were the same guy. I’d see Mickey Rooney in a movie and be like “Wow, he’s looking pretty good for his age,” thinking he was a man 32 years his senior and/or dead.
I finally twigged when I eventually saw Iron Man 2 (2009) and was like “How is he doing this?!” and actually looked him up.