Just don't ever: grow old, break an arm/hand, become disabled, get weakened by illness, or be born a smaller person. Then yes, you'll always have an extra hand for off-wheek controls.
For everyone else, we've had automatic cars for forever. There's also a video online of a man with no arms who learned how to drive their car without them.
Edit: changed to be specific about the one hand on the wheel.
Consider that at a critical moment the difference between moving a thumb and moving ones whole arm and hand could be the difference between life and death.
EDIT: fixed typos