But...can they do over 280,000 miles on their original rings and pistons and still burn no oil over 5000 miles of hard use?

Seriously, 8 quarts in, 8 quarts out. No leaks, no drips, nothing burned, and the oil still looks in pretty decent shape (I mean, as far as you can tell looking at oil.) There is something to be said for an overbuilt, under-stressed engine.