I suspect Rainboe forgot about a couple of AC powered electric pumps.
Anyway, the original B747 was certainly not fool-proof with regard to hydraulics.
Witness JAL with all fluid loss.
There was only one first generation wide-body jet airliner that had hydraulic fusing as part of the original design (not added on, later)....the Lockheed L1011.
And yes, it has, just like the B747, four separate hydraulic systems.
A superb design.
