By this logic should we have autonomous refueling already?
It's been done a few times.[1][2] The systems are rather slow and clunky, but work. Dealing with all the variation between cars runs up the cost.
Tesla has a charging robot.[3] This is much easier, since Tesla controls both sides of the interface. The car actively cooperates, opening the charging port door. Tesla also interlocks the car so that you can't drive away while plugged in. I'm surprised that Tesla hasn't deployed those robot chargers yet.
They did deploy one station, between SF and LA. They say it has barely got any traffic, so they aren't planning to build any more. Others have pointed out that building the station was a requirement to get some CA tax benefit.