Naturally, any setup that gets you a new car every three years is going to have drawbacks. Notice that I said that "if I were to look at a new Audi", which is not something I would do until I have set myself up quite comfortably. Some people would have a higher priority for cars, and want a new car every three years, and heck, if I am a bit older and my finances would allow such comfortably then I would honestly consider it very seriously.
In the near future, I would rather buy a second hand one that has a couple of years behind it for the savings and then pay that off, while having a third party maintenance cover (if auto, due to cost of replacement being so high).