Mercedes once had a famous ad campaign that boasted of their cars lasting a million miles. Nothing could be less desirable today.
Cars that last "forever" delay the adoption of new technologies "forever". Vast improvements in fuel economy, emissions, occupant safety, driver assistance and, soon, autonomy, are all amplified for society by turnover in the fleet. That means we need cars to get off the road after, say, a decade or so.
Cars have become more of a disposable appliance, less something that is repaired forever like darning a pair of old socks. We are also in a leasing culture in recent years, which also facilitates faster dissatisfaction with an old car.
The average age of a car on American roads is around 11.5 years, thanks largely to the 2008 recession delaying a lot of car purchases. But as that calamity recedes into the rear view mirror of economic history, we are getting back to our normal 8.5 years average vehicle age. That speaks to about 130,000 miles on a car, maybe 200,000 once it goes through a few subsequent owners and then the junkyard. A long way from a million miles and that's the way it needs to be for the benefit of all of us.