They are located only 3 miles from where I live. Once I was looking for special windows for a UK 4 mm project and they invited me over and let me look through all of the inventory shelves of windows to see if any would be right for the project. I found some O scale windows that actually worked.
But all things change. So many model railroad structures are now sold RTR and the dollhouse business must also be dying. Architects no longer need to use detail parts when they can 3 D render and 3 D print if physical models are needed.
While I recognize the winds of change, Grandt Line was a truly California/US business and it is sad to hear of their impending passing.