Ref continue or not (LAX - PHX), the situations were vastly different. The general mantra for a 747 is continue if it’s safe to do so. Considerations include
Severe damage or not? Engine surges/failures can occur for multiple reasons, eg. guide vane angle failure (surge, not severe damage), or bits missing (surge/failure, structural damage), fuel metering unit failure (flameout, not severe damage).
Terrain clearance emergency turn procedure? If there is one once completed there’s probably not enough fuel to reach destination. No ETP and you might have enough gas to get home.
Fuel loading, there might simply be not enough fuel on board to get home one eng inop, if you’re lucky and are carrying a lot of contingency fuel there might be enough.
En route MSA’s. If there are MSA’s above the two eng inop max ceiling then either a reroute or divert is required. A reroute might mean an increase to trip fuel which now means you’re short of fuel.
En route weathers. If Goose, Gander, Kef, Prestwick etc are wide open you might consider continuing as you could get in two eng inop. If the enroute wx is crappy and you don’t fancy having a go two eng inop (go around is very difficult / impossible after gear extension) you would divert.
Decompression fuel. If continuing one eng inop do you still have enough fuel to perform an emergency descent at the critical point mid Atlantic and still be able to reach a suitable airfield with reserves intact. And is the weather at those suitable airfield good enough?
These are just some of the concerns a 747 crew need to address. The 747 is designed to be “go minded”. Some crews have quite correctly elected to continue, other crews have quite correctly elected to return or divert.
Unless you are type rated on the aircraft in question, and have all the information that that particular crew had available to them, you are quite simply not qualified to pass judgement on a crews decision.
Hope that helps.
LD