8 years is considering that you drive 20,000 miles a year and that the car will break down at 150,000.
The vast majority of modern cars of decent quality can easily go ~250,000 miles, and Iโve rarely ever met anyone thatโs driven more then 10,000 miles a year.
That means you can probably squeeze a good 15-20 years out of a modern car based on how well you take care of it and how much you drive.
There is a reason warlords and ISIS use Toyota trucks. Iโm pretty sure you could run those over with a tank and they would still run fine for 400k miles.
The Japanese car in our family is an absolute workhorse that was driving 15k a year and it is still going strong 16 years into its life with 250k miles.