Maybe not quite cardboard, but I had similar thoughts reading that. Relatively fancy industrial design, entirely custom board apparently (i.e. not using an SBC or SoM) sounds expensive up front. But it's hard to judge without more background knowledge (estimated volume, covering up-front expenses is what venture funding is kind of for, exact requirements software-side ... if there is a more indepth breakdown I'd love to read it!) and in the end it'd been a good chunk of luck to hit the right path at the right time to avoid the pandemic struggles.