once you get above 300 volts you have to start really dealing with NFPA-70E Arc flash regulations (below 300 is only an issue if "exposed" other wise it is avoid contact).
If you then start getting above 750 and in the kV range you start dealing with hard regulations around approach boundaries
751-15kV is 2'2" restricted boundaries (requires PPE and training) and 7" prohibited boundary (meaning you can't be within 7 inches of a live line in that range period)
My bet is that no car manufacturer wants to deal with having to design a charging station standard which requires people to hook it up, step away, AND have a method for ensuring that there is zero possibility of someone within the area.
When you have power in that voltage range someone will be liable for safety in that area, and car manufactures can not insure that the operator of the car and charging station have had the appropriate training or PPE available so they most likely won't go there. Even on industrial equipment that uses this level voltage most OEMs have safety interlocks so that you can't accidentally get into an energized compartment.
Sorry you just won't see real high voltage charging systems for consumer cars. This is one of the reasons they will have to figure out how to deal with the current side of the problem.