My strategy when I get repetitious “whys” has been to ask “why what?”
Make them process the answer you just gave them and reformulate it into a question.
If they don’t do a good job just say "I don’t understand your question, can you ask it in another way? "
Kids like the ‘why’ game because it’s easy entertainment. Just make it less easy.
Maybe you should secretly learn to drive and then take her on a surprise outing.