Employing labor full time is incredibly expensive in the US. Once you include overhead, taxes, benefits, etc. you can easily be paying 2x wage for a worker. Not to mention buying the goods. So yeah the parts for the guitar might cost X, but then it costs Y to store them and Z for the space to assemble them then A to pay the workers and B to ship them and C to market. It adds up. Without jumping to the EVILS of "Capitalism" a business costs money to run. I can't imagine guitar manufacturer margins are anything close to techs, probably <5%. Gemini tells me industry is around 3.8% so I don't think I am far off.