I said there are many more cars (foreign AND domestic) that don't reach 300,000 miles than those that do. It's just, of the ones I've heard of that are well over 300,000 miles, they seem to overwhelmingly be American V8 engines - more specifically the Chevrolet 350 or some variant of it. And many of these engines in their respective applications are by no means babied whatsoever and are driven rough, pushed hard, and often not well maintained.
There's a bad apple in every bunch. For those of you who know, my WRX hasn't always lived up to the Japanese reliability reputation that Subarus generally hold.
Slightly off topic:
Discussion about engine longevity IWSTI
Good guys giving some love to American cars there that can run 10 seconds in the 1/4 and still be a reliable daily driver.