Why does the cargo hold need to be pressurised? Just think a bit about the cargo carried. You can't very well take up a load anything to have it freeze, expand, burst, etc. It could be organic in nature as well..
We're starting to get into science fiction here. What is really needed is fire supression via injectable chemicals and foam. Fedex has developed such a system. In the interim, a smoke displacement hood may have saved this crew which, for a billion-dollar company wouldn't amount to pocket change. What you htave here is penny pinching done by actuaries in the bean counting deparment which runs the flight operations group at most airlines.