I think the point DM is trying to make is; because Alonso's engines have gone the full race distance in all but one race, whereas other driver's have had more DNFs, his engines have the potential to be more prone to failure come the end of the season.
On the other hand, Ferrari may have built an absolute rock of an engine, we just don't know.
But the engines are designed with doing the full season. I think most have pretty much got rock solid engines especially with the engine freeze. Sauber ain't losing engines either so I would not be thinking too much into such hopes