gf:
Are you contending that air carriers can plan oceanic crossing with a "wet footprint" in the event of depressurization? I doubt that.
Without a wet footprint would be much more desirable.
I can only speak of my limited experience in this reqard. I never flew International but I had a few years of flying the L-1011 from LAX to Honolulu, which is a very long over-water segment. San Francisco and Hilo were our deversionary alternates unless a problem happened with 300 miles of departure or arrival.
In the event of a loss of pressurization at the ETP we could indeed make Hilo or San Francisco at 10,000 feet without risk of a wet footprint. Or, we could make Hilo or San Francisco with the loss of one engine, whether we had pressurization or not. The diversion at the ETP saved about 200 miles, which is a fair about of extra fuel.