Well, yeah, that's what cars do. Trading cars every 5 or so years is a great way to empty your bank accounts, as you are repeatedly taking the biggest punch in the face on depreciation. You should expect a car to lose basically all of its value and therefore keep it for at least a decade to wring more value out of it.
Well, there's reality and then there are some things that Musk has said. I would not use the word "supposed to appreciate". That was a ridiculous, stupid, and yes, "Ludicrous" notion that was definitely never going to happen. Used cars are not going to appreciate above what a new car would be. You should not have believed that for a second.