It entirely dependent on what is being made, and you don’t have the benefit of spreading the load for R&D across vast areas, bulk buys - after paying bills, patents, machines, staff, marketing etc. He still has to pay himself a wage, there will be less flex in the system.
Fender can make a Squier bass, or Harley Benton can make one and sell for about £100 (lots of stuff from shared factories). Regardless of quality of instrument there is absolutely no way with my small premises I could make one at that cost