Chess involves an opponent that's doing their best to cause trouble.
Driving on icy gravel, that's just a physics simulation, with no opponents.
The hard part of self-driving is vision, with hard constraints on real-time and power supply — how long that takes (especially given the enormous pile of scenarios we don't think about when trying to list them but do know how to deal with when we encounter them), I don't want to guess, as I think it could be anywhere from negative 6 months to positive 16 years.
