First off, within the bounds of runway performance, it generally takes a bigger engine to haul the weight (mass, for you European folks) of all the aeroplane and fuel, off of said runway...for that longer route.
Twins, especially.
Three or four engine types are (usually) not so compromised.
Therefore, the engines on a twin are just slightly larger than they need to be for the range anticipated.
Enroute failures enter into the picture, as well.
Many compromises.