Interesting excercise in the sim. In reality the hydraulic system is the most reliable on the aircraft. Complete Failure of one system is incredibly rare failure of two at the same time is only likely to happen with a catastrophic/ uncontained engine failure. Out of interest, how many have lost one hyd system (and what caused it)?
I lost the blue system once, due to a leak that MX was unable to find. 10+ years on the A320 now.