It's been many, many years since I worked for the first EDM company that was able to do 5 axis wire EDM. 0.0005" was the standard tolerance for their basic machines, and that was a barn door to the "premium" machines. All it took was brass .010" wire; clean water; and time. One of my first training for programming involved a hexagon "cylinder" with a full 360* twist in a 2" thick piece of steel that was accurate to 3 decimal places... nearly 18 years ago. If you were willing to set insanely long cut times... 50 millionths was available. No idea what today's best EDMs are capable of.
EDM is an amazing technology, albeit not the fastest.
That's not even considering the accuracy of the die-sinking machines which used graphite "electrodes" that were used to make things like cell phone case pieces, etc.... the metal moulds were only limited by the accuracy of the CNC machine that had machined the chunk of graphite that was making the metal mould....