Perhaps the key factor that was brought up about that BA decision to continue was that the 744 is in fact certified for continued operation on 3 engines.
It wasn’t based on some general philosophy of 4 engine airplanes, rather that the -400 specifically had sufficient redundancy on the other engines, eg electric sources etc.
Further, unless it's rather heavy, a 747-400 or -8 will cruise quite happily at 35k on three engines (higher if it's light) - although it does burn more fuel doing it than on four (like YRP I'm not sure about the older 747s). Good luck doing that on
any twin with an engine out...
As I recall, none of the 747-400/-8 engines have windmilling restrictions provided oil pressure remains positive (the windmilling core will provide sufficient oil pressure assuming the oil system is otherwise healthy).
The BA is the best knows case of a 747 crossing the Atlantic after an engine failure at or just after takeoff (presumably because they ran low on fuel and diverted), it's certainty
not the only one.