In any event, it does not make sense to buy a new car with an engine that went out of production prior to purchase. If I want more power in a new Morgan, the Roadster 3.7 is the wiser route from any point of view.
Whether or not the engine is in production is not a critera I would worry about when buying a new Mog or any other car, for instance the 911 is about to get a new engine but that wouldn't put me off the current model, and even when the engine is still current the specs change, ie euroVI emissions will soon be upon us
You say the Roadster 3.7 is the wiser route, but when did wisdom have anything to do with buying Morgans?