As someone who's spent the majority of my adult working life in the automotive industry I can say that yes the future is being designed very much for your to be replaced every 5-6 years like your cell phone.
Three facts point me to this belief. One the old saying they don't build them like they used too. I have a 2020 Nissan Pathfinder in my shop today with a failed MAF sensor at 59k miles, the car can't run without this sensor it's in limp mode. This is not uncommon on vehicle built after 2018. I'm seeing 1-2 year old cars with complete HVAC failure and they require a new epa refrigerant called 1234yf it's $20 an oz your old 134a was $20 a lbs! So your 2 year old car now needs $900 worth of gas to charge before I find the leak! This week alone I've replace bearings on 4 vehicles less than 3 years old all under 75k miles it's ludicrous. Great for my business but all of them are junk not even my beloved Toyotas are built to last anymore. You simply won't see anything built after 2018 on the road in 10-15-20 years, they won't last.
Second if your blessed to find a vehicle that lasted this long inevitably the electronics will wear down after about 10 years. Voltage reference sensors require replacement on average 5-10 years, however the manufactures are not making them after 7 years. For example you have a 2010 F150 if the Vvt sensors fail you can get them aftermarket because they used the same Vvt solenoids for the last 15 years. The new vehicles are using a completely different Vvt system and they've changed 4 times in 4 years. Your 2018 F150 Vvt won't work in a 2021 model. The aftermarket world isn't going to buy patents and mass produce Vvt solenoids that only cover 2 year models it's not profitable. This is just one example your new vehicle has an average of 60 voltage refrence sensors to operate the vehicle. Just one of those out of production and your car is now obsolete.
Third the cost, new trucks are going for 80-90k cars are going for 40-60k. Most people are never going to pay off they're using 8 year terms to finance. Your upside down the entire time you pay on these vehicles so every few years people trade them in and get the latest model holding a loan payment forever with negative equity. What I see the finance side of the business migrating to is more of a lease type ownership. You like this vehicle make a smaller interest only payment for two or three years and we will let your trade it back to us at full value for a new model lease in two or three years. The manufacture essentially rents the vehicles long term through dealerships and the sells them as used certified vehicles 3 model years later to the subprime market. But as a consumer you never actually own this vehicle it's to expensive to own it.