Hardware development still has fundamental physical constraints that software doesn't - material costs, manufacturing complexity, and safety requirements create barriers that CAD and 3D printing alone can't overcome.
I noted in a different discussion here that I'm about to the point where my next computer is going to be a Raspberry Pi 500 w/ a second gen. Wacom One 13 display w/ stylus and touch and a battery, for which assemblage I'll make a folding tablet shell...
Or, maybe it will be a shell/case for the Pilet which I'll be getting from Kickstarter.
Development, yes. Production, no. That's really where the rubber meets the road. Upfront costs, profit margins, and scaling challenges, are not comparable.