At the end of the day, with current technology a driver will ALWAYS be better in wet conditions. I have never seen a system like that that performs in the wet. It's always dangerous and would be worse in the wet.
Unfortunately the driver made a huge error and was going much too fast for the conditions. Such a horrible accident. But it's part of the sport, and it is bound to happen every now and then.
Don't know why they don't (some tracks do) just have cranes outside of the track that can literally pick the vehicle up and over the wall without going on the track. Make the whole recovery much faster and much safer.