You actually don't want all metal parts for how voron printers are designed. A lot of parts on the gantry rely on the flex of the plastic to be able to do self calibration and leveling. Metal would be more likely to fatigue and undergo plastic deformation that would bring it out out of spec or into a complete failure mode.

there are CNCd parts available from various vendors, but they usually have design alterations to account for the aforementioned increase flex tolerance and also to make them more economical (or just possible) to machine.

Those parts usually are heavier as well and can have a negative effect on the resonance and inertia of the gantries reducing print speed.

There's been a lot of discussion on this at various points in the voron design discord (serious discoverability problem compared to forums and the such :P ) about this.

In terms of price, electronics and motions components are just expensive, especially if you want reliable parts. Metal parts would also increase the price because machining is more expensive than printing by quite a bit.