The car life cycle has many stages. It is a little known fact that during the final stage the car stops using internal combustion as a means of propulsion and instead uses sheer will to move forward. The start of this life cycle is often marked by the formation of rust holes.
Since the car no longer requires a non-metaphysical propulsion system it has no need for its components. This is why it goes about the process of shedding its parts.
Trivial components often mark the start of this process: rear view mirrors, large portions of the dash board, mud flaps, windshield wipers, speed stripes, gear shift knobs, catalytic converter heat shields, etc.
Non-trivial components follow the shedding of trivial components: doors, bumpers (been there, done that), sections of the exhaust system, hoses, seats (done that too), things that make your car make a loud rumbling sound, parts of the electrical system, etc.
Often this life cycle can last decades. One day you will find that you have actually been running to work holding a steering wheel for several weeks. Time to get a new rust bucket.