While cars have gotten more reliable, they have also reduced their service life drastically.
Very few will go 20 years and most will be obsoleted in 10 when critical components will no longer be available.
I had to dump a perfectly good 1994 van because the throttle valve is NLA similar with a 2005 van because the computer cable connector is NLA.
Being a commonwealth country we got the junk the Pommies made foisted upon us for decades till the late 90's when import quotas were abolished.
The locally made cars ( scaled down versions of USA models then had to compete with European vehicles and their quality went forward leaps & bounds.
By the 70's they were all fully dipped.
I rather think the lack of quality in US vehicles had more to do with the protection of the market than anything else.
When Yamaha brought out the SR 500 followe by the V twin based on it, Harley lost their exemption for Californian EPA requirements as Yamaha showed they could be exceeded .
So HD had a big shake up and went from a cheaply made local embarassment to a modern motorcycle at a substantially higher price
I have to disagree about service life. A vehicle with 100,000 miles on it used to be a real achievement. One with 200,000 had at least one overhaul and you heard about it in a letter from your great Aunt in Nebraska whose neighbor was trying to sell it. My first car was a 1965 Mercury which was seven years old and I bought it in 1972 (for $210, amazing). It had 78,000 miles on it. It already had rusted through in both rear fenders. My 2001 Dodge Dakota is approaching 18 years old and is finally starting to rust (in places where pickups tend to, for the most part). It runs great and I plan to keep it for the foreseeable future.
It's very common to find people selling cars with well over 100,000 miles on them. My sister in law drives a Dodge Charger with 245,000 miles on it. It's getting tired out but fortuantely she's got a lifetime powertrain warranty on it. And trucks? People are selling pickups and large SUV's with 200,000 miles on them and not at giveaway prices.
So I definitely disagree about service life. (BTW I own a 2005 Lexus with 165,000 miles on it and it feels and runs like new.) Cars in the old days at half a dozen years started becoming clunkers and beaters. Not anymore.
Re NLA parts, at least in the US car makers have to provide repair parts for a certain number of years, longer periods for parts that are necessary to run or meet emissions or safety, but nobody as a matter of SOP stocks parts for 20 year old vehicles. That's why there is an aftermarket, Ebay, and junkyards.
I have no doubt that foreign competition forced the US automakers to greatly up their game and I'm glad that happened. Honestly, they have done a great job of making a better, more reliable and longer lasting product than when they had the market sewn up.