Is it unusual? Yes. I've seen many cars that were highly abused last much longer. Hell, you could have probably driven the car that long with out ever doing any maintenance other than topping off the oil and it would last over 100k miles.
If the turbo and shortblock really are both gone my best guess is that it had no oil in it at the time it failed (less than 1qt.). Something may have happened to cause the oil to drain, but it would be hard not to notice.
It's hard to say what happened without actually looking at the car.