The lathe duplicator is fairly simple, you are using it on a round piece and the stylus follows the curves of the template and the cutter goes where the stylus goes. Most of the cutters are 1/4" so you can see that it is not going to follow into tight corners and intricate designs less than 1/4".
There have been pantograph type duplicators that use a stylus also but use a router mounted to a plate is doing the cutting, bits can be changed to get closer but the outline of the stock and some of the inletting can be done, but there is also a lot of hand inletting to do and I'm sure that is the came with the CNC machines.
