My father used to drive up to 100k miles a year, he is a real estate agent (he has his broker's license) and did a lot of travelling out of state. The only car he ever bought new, was a 1981 VW Rabbit diesel, he put 100k miles on it in the first year, and the car had 317k miles on it when someone ran into him and totalled the car a couple years later. He sold the engine to a family friend, and it was still running years later. He is getting older now and doesn't drive quite as much, I think he is down to only around 40k miles a year.
My wife had a VW Rabbit diesel that rolled over 200k miles before we got rid of it. It was bought new by her sister, and then passed onto my wife when she was in college. It was still running for at least a few years after we sold it.
My wife and I were the 2nd owners of a Volvo 240 Wagon that had over 220k miles on it, we'd probably still own it if a Dodge Ram truck hadn't plowed into my wife (my 10 week old son was also in the car) in front of our house at more than 60 mph. The car did its job though and protected my wife and son, no injuries at all.
I used to drive 25k miles a year before my wife and I settled down and started having kids, now it is closer to 15k miles a year. I can't imagine putting a million miles on the same car, I'd get tired of that. The longest I've owned a car is 9 1/2 years, and I put 116k miles on it (a Dodge Neon, my first new car) before I sold it a couple of years ago. I've driven nearly 400k miles since I started driving more than 20 years ago, but I like to drive, and would rather drive across the country than fly. My wife and I own four cars now, and split the driving among them, the most any one of them gets is around 10k miles a year.
