Sometimes, when it comes to very 'specialist' gear, once everybody that wanted one got theirs, that's that, if you keep to your original vision strictly.
Or you can have a very original vision, sell all of that you can, then morph the name and product to keep going, like Fly guitars that look like Teles instead of Parker's original, or Hartke cabinets that don't have aluminum drivers.
Of course, the third option is becoming increasingly popular: Sell your company to Gibson or FMIC, get a big check, hang around a year or two as a 'consultant' (at least you can come back from Tahiti or the North Shore to get trotted out at the NAMM Show in the booth), then go back into business after the non-compete runs out. Not bad work if you can get it.
J o e y