Got a different take on that. Seen a few old Mazaks run that long, but they're usually held together with baling wire and prayers by that point. The real story is the mountain of cash spent on parts and downtime to keep it limping along.
Ever read that article about sunk cost fallacy with old machines? You keep throwing money at it because you already spent so much, not because it makes sense. That's how shops end up with those "million dollar" Mazaks.