The “biggest decrease of value” assumes that, to you, the value of the car is determined by what you could sell it for. But that’s not the case. To you, the value of the car is what you spent on it. You then amortize that value of the car over the years you operate it.

This. I just was able to buy my first ever "new" new car after years of every "new" car being at minimum 10 years old. I've got an '06 Forester with nearly 200k miles on it, and I'm hoping this new one will last as long (but I kind of doubt it).

Regardless, I'm not leasing, not planning on selling in 5 years. To me, the peace of mind of a new car warranty is worth it and it gets way better mileage than the old Forester.