Having just gotten a car, I can unequivocally say that they are nothing alike!
Cars = expensive to buy, they break, then are expensive to repair. Can't drop them in a backpack and take them with you everywhere. If the car starts to sass you, you can't put it back in it's box and bury it in a closet.
Tarot = MUCH cheaper. ($20 deck or $20,000 car?) Doesn't randomly drop parts or run out of gas in the middle of nowhere. Eminently portable, and do a much better job of talking with you than a car does. Don't have to pay registration, plate fees, or insurance on a tarot deck.
The thing is with me is that I *can't* buy a deck that I won't use. No collector decks for me!! I usually end up buying mine used; the only onesI have that are new were either just-released or presents.
That way, I don't have new-in-shrink decks giving me the hairy eyeball for leaving them to collect dust on a shelf, and it won't break my heart or pocketbook to have to replace them if the kids draw on them.
Illy